GENWiki

Premier IT Outsourcing and Support Services within the UK

User Tools

Site Tools


rfc:rfc3094

Network Working Group D. Sprague Request for Comments: 3094 R. Benedyk Category: Informational D. Brendes

                                                             J. Keller
                                                               Tekelec
                                                            April 2001
            Tekelec's Transport Adapter Layer Interface

Status of this Memo

 This memo provides information for the Internet community.  It does
 not specify an Internet standard of any kind.  Distribution of this
 memo is unlimited.

Copyright Notice

 Copyright (C) The Internet Society (2001).  All Rights Reserved.

IESG Note:

 Readers should note that this memo presents a vendor's alternative to
 standards track technology being developed by the IETF SIGTRAN
 Working Group.  The technology presented in this memo has not been
 reviewed by the IETF for its technical soundness or completeness.
 Potential users of this type of technology are urged to examine the
 SIGTRAN work before deciding to use the technology described here.

Abstract

 This document proposes the interfaces of a Signaling Gateway, which
 provides interworking between the Switched Circuit Network (SCN) and
 an IP network.  Since the Gateway is the central point of signaling
 information, not only does it provide transportation of signaling
 from one network to another, but it can also provide additional
 functions such as protocol translation, security screening, routing
 information, and seamless access to Intelligent Network (IN) services
 on both networks.
 The Transport Adapter Layer Interface (TALI) is the proposed
 interface, which provides TCAP (Transaction Capability Application
 Part), ISUP (ISDN User Part), and MTP (Mail Transport Protocol)
 messaging over TCP/IP.  In addition, TALI provides SCCP (Signalling
 Connection Control Part) Management (SCMG), MTP Primitives, dynamic
 registration of circuits, and routing of call control messages based
 on circuit location.

Sprague, et al. Informational [Page 1] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

Table of Contents

 1. Introduction                                                    4
 2. Overview of the TALI Protocol                                   6
 2.1 Traditional PSTN SS7 Networks                                  6
 2.2 Converged SS7 Networks                                         8
 2.3 TALI Protocol Stack Overview                                  10
 2.3.1 An Alternate TALI Protocol Stack using the SAAL Layer       13
 2.3.2 An Alternate TALI Protocol Stack using SCTP                 15
 2.4 Inputs to the TALI Version 1.0 State Machine                  15
 3. TALI Version 1.0                                               17
 3.1 Overview of the TALI Message Structure                        17
 3.1.1 Types of TALI Fields                                        19
 3.2 Detailed TALI Message Structure                               20
 3.2.1 TALI Peer to Peer Messages                                  20
 3.2.1.1 Test Message (test)                                       20
 3.2.1.2 Allow Message (allo)                                      21
 3.2.1.3 Prohibit Message (proh)                                   21
 3.2.1.4 Prohibit Acknowledgement Message (proa)                   21
 3.2.1.5 Monitor Message (moni)                                    22
 3.2.1.6 Monitor Acknowledge Message (mona)                        22
 3.2.2 Service Messages                                            23
 3.2.2.1 SCCP Service Message (sccp)                               23
 3.2.2.1.1 SCCP Encapsulation using TALI                           25
 3.2.2.2 ISUP Service Message (isot)                               27
 3.2.2.2.1 ISUP Encapsulation using TALI                           27
 3.2.2.3 MTP3 Service Message (mtp3)                               28
 3.2.2.3.1 MTP3 Encapsulation using TALI                           29
 3.2.2.4 SAAL Service Message (saal)                               30
 3.2.2.4.1 MTP3 and SAAL Peer to Peer Encapsulation using TALI     31
 3.3 TALI Timers                                                   34
 3.3.1 T1 Timer                                                    34
 3.3.2 T2 Timer                                                    34
 3.3.3 T3 Timer                                                    34
 3.3.4 T4 Timer                                                    34
 3.3.5 Recommended Defaults and Ranges for the TALI Timers         35
 3.4 TALI User Events                                              35
 3.4.1 Management Open Socket Event                                35
 3.4.2 Management Close Socket Event                               36
 3.4.3 Management Allow Traffic Event                              36
 3.4.4 Management Prohibit Traffic Event                           36
 3.5 Other Implementation Dependent TALI Events                    37
 3.6 TALI States                                                   37
 3.7 TALI Version 1.0 State Machine                                38
 3.7.1 State Machine Concepts                                      38
 3.7.1.1 General Protocol Rules                                    38
 3.7.1.2 Graceful Shutdown of a Socket                             39
 3.7.1.3 TALI Protocol Violations                                  39

Sprague, et al. Informational [Page 2] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

 3.7.2 The State Machine                                           40
 3.8 TALI 1.0 Implementation Notes                                 42
 3.8.1 Failure on a TCP/IP Socket                                  42
 3.8.2 Congestion on a TCP/IP Socket                               43
 3.9 TALI 1.0 Limitations                                          43
 4. TALI Version 2.0                                               43
 4.1 Overview of TALI Version 2.0 Features                         45
 4.2 TALI Version Identification                                   47
 4.3 Backwards Compatibility                                       50
 4.3.1 Generating Protocol Violations based on Received Messages   53
 4.4 Overview of the TALI Message Structure                        55
 4.4.1 Types of TALI Fields                                        55
 4.5 Detailed TALI Message Structures for New 2.0 Opcodes          58
 4.5.1 Management Message (mgmt)                                   60
 4.5.1.1 Routing Key Registration Primitive (rkrp)                 61
 4.5.1.1.1 RKRP Data Structures                                    65
 4.5.1.1.1.1 Common Fields in all RKRP Messages                    65
 4.5.1.1.1.2 CIC Based Routing Key Operations                      67
 4.5.1.1.1.3 SCCP Routing Key Operations                           71
 4.5.1.1.1.4 DPC-SI, DPC and SI based Routing Key Operations       74
 4.5.1.1.1.5 Default Routing Key Operations                        76
 4.5.1.1.1.6 Support for Multiple RKRP Registration Operations     78
 4.5.1.1.1.6.1 Multiple Registrations Support                      78
 4.5.1.1.1.6.2 Multiple RKRP Operations in a Single Message        80
 4.5.1.2 MTP3 Primitive (mtpp)                                     82
 4.5.1.3 Socket Option Registration Primitive (sorp)               87
 4.5.2 Extended Service Message (xsrv)                             91
 4.5.3 Special Message (spcl)                                      92
 4.5.3.1 Special Messages Not Supported (smns)                     93
 4.5.3.2 Query Message (qury)                                      93
 4.5.3.3 Reply Message (rply)                                      94
 4.5.3.4 Unsolicited Information Message (USIM)                    95
 4.6 TALI Timers                                                   95
 4.7 TALI User Events                                              95
 4.8 TALI States                                                   96
 4.9 TALI Version 2.0 State Machine                                96
 4.9.1 State Machine Concepts                                      96
 4.9.1.1 General Protocol Rules                                    96
 4.9.1.2 Graceful Shutdown of a Socket                             97
 4.9.1.3 TALI Protocol Violations                                  97
 4.9.2 The State Machine                                           97
 4.10 TALI 2.0 Specification Limitations                          101
 5. Success/Failure Codes                                         101
 6. Security Considerations                                       102
 7. References                                                    102
 8. Acknowledgments                                               103
 9. Authors' Addresses                                            104
 10. Full Copyright Statement                                     105

Sprague, et al. Informational [Page 3] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

1. Introduction

 This document is organized into the following 6 sections:
  1. Introduction to the document
  2. Overview of the TALI Protocol
  3. TALI Version 1.0
  4. TALI Version 2.0
  5. Success/Failure Codes
  6. Security Considerations
 The following terms are used throughout this document.
 Circuit Identification Code (CIC):
 A field identifying the circuit being setup or released.  Depending
 on SI and MSU Type, this field can be 12, 14 or 32 bits.
 Changeover/Changeback (co/cb):
 SS7 MTP3 procedure related to link failure and re-establishment.
 Far End (FE):
 The remote endpoint of a socket connection.
 Far End Allowed (FEA):
 The FE is ready to use the socket for service PDUs.
 Far End Prohibited (FEP):
 The FE is not ready to use the socket for service PDUs.
 Intelligent Network (IN):
 A network that allows functionality to be distributed flexibly at a
 variety of nodes on and off the network and allows the architecture
 to be modified to control the services.
 Management ATM Adaptation Layer (MAAL):
 This layer is a component of SAAL.  This layer maps requests and
 indications between the System Management for the SG and the other
 SAAL layers.  MAAL includes interfaces to/from SSCOP, SSCF, and
 system management.  More information can be found in T1.652.
 Media Gateway (MG):
 A MG terminates SCN media streams, packetizes the media data, if it
 is not already packetized, and delivers packetized traffic  to the
 packet network.  It performs these functions in reverse order for
 media streams flowing from the packet network to the SCN.

Sprague, et al. Informational [Page 4] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

 Media Gateway Controller (MGC):
 An MGC handles the registration and management of resources at the
 MG.  The MGC may have the ability to authorize resource usage based
 on local policy.  For signaling transport purposes, the MGC serves as
 a possible termination and origination point for SCN application
 protocols, such as SS7 ISDN User Part and Q.931/DSS1.
 MTP3 Framing (MTP3F):
 TALI does not require full MTP3 procedures support but rather uses
 the MTP3 framing structure (ie: SIO, Routing Label, etc)
 Near End (NE):
 The local endpoint of a socket connection.
 Near End Allowed (NEA):
 The NE is ready to use the socket for service PDUs.
 Near End Prohibited (NEP):
 The NE is not ready to use the socket for service PDUs.
 Q.BICC ISUP:
 An ISUP+ variant that uses 32 bit CIC codes instead of 14/12 bit CIC
 codes.  ISUP+, or Q.BICC ISUP, is based on the Q.765.BICC
 specification currently being developed in ITU Study Group 11.
 Signaling ATM Adaptation Layer (SAAL):
 This layer is the equivalent of MTP-2 for ATM High Speed Links
 carrying SS7 Traffic as described in GR-2878-CORE [8].  SAAL includes
 SSCF, SSCOP and MAAL.
 Signaling Gateway (SG):
 An SG is a signaling agent that receives/sends SCN native signaling
 at the edge of the IP network.  The SG function may relay, translate
 or terminate SS7 signaling in an SS7-Internet Gateway.  The SG
 function may also be co-resident with the MGC/MG functions to process
 SCN signaling associated with line or trunk terminations controlled
 by the MG (e.g., signaling backhaul).
 Service Specific Coordination Function (SSCF):
 This layer is a component of SAAL.  This layer maps the services
 provided by the lower layers of the SAAL to the needs of a specific
 higher layer user.  In the case of the STP, the higher layer user is
 the MTP-3 protocol, and the SSCF required is that as defined by
 T1.645: SSCF for Support of Signaling at the Network Node Interface
 (SSCF at the NNI).  More information can be found in T1.645.  SSCF
 provides the interface between SSCOP and MTP3 and includes the
 following functions:

Sprague, et al. Informational [Page 5] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

  1. Local Retrieve of messages to support link changeover procedures
  2. Flow control with four levels of congestion
 Switched Circuit Network (SCN):
 The term SCN is used to refer to a network that carries traffic
 within channelized bearers of pre-defined sizes.  Examples include
 Public Switched Telephone Networks (PSTNs) and Public Land Mobile
 Networks (PLMNs).  Examples of signaling protocols used in SCN
 include Q.931, SS7 MTP Level 3 and SS7 Application/User parts.
 Service Specific Connection Oriented Protocol (SSCOP):
 This layer is a component of SAAL.  This layer provides reliable
 point to point data transfer with sequence integrity and error
 recovery by selective retransmission.  Protocol layer interfaces are
 described in T1.637.  Aspects of the protocol include flow control,
 connection control, error reporting to layer management, connection
 maintenance in the prolonged absence of data transfer, local data
 retrieval by the user of the SSCOP, error detection of protocol
 control information and status reporting.  SSCOP provides the link
 layer functions that are:
  1. In-Sequence Delivery
  2. Flow Control
  3. Error Detection/Correction
  4. Keep Alive
  5. Local Data Retrieval
  6. Connection Control
  7. Protocol Error Detection and Recovery
 Signaling Transfer Point (STP):
 Packet switches that provide CCS message routing and transport.  They
 are stored programmed switches that use information contained in the
 message in conjunction with information stored in memory to route the
 message to the appropriate destination signaling point.

2. Overview of the TALI Protocol

2.1 Traditional PSTN SS7 Networks

 The traditional PSTN SS7 network consists of 3 types of devices
 connected via dedicated SS7 signaling links.
 The 3 primary device types for PSTN networks are:
  • SSP: Signaling Service Point. These nodes act as endpoints in

the SS7 network, originating SS7 messages as users attempt to

    place phone calls.  These nodes contain interfaces into the SS7
    data network and the SS7 voice network.

Sprague, et al. Informational [Page 6] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

  • STP: Signaling Transfer Point. These nodes act primarily as

switches, switching SS7 traffic from node to node throughout the

    network until it reaches another endpoint.  An important feature
    of each STP is to provide SS7 network management functionality
    that allows messages to be delivered even when links and devices
    fail.  STPs also sometimes provide database type services, such as
    Global Title Translations and Local Number Portability.
  • SCP: Signaling Control Point. These nodes act as databases.

These nodes contain stored data that is used to turn SS7 Queries

    into SS7 Replies.
 There are 3 primary types of dedicated SS7 signaling links:
  • 56Kbps SS7 (DS0, V35, OCU) links. These links implement the MTP-1

and MTP-2 protocols as defined in [1].

  • DS1 High Speed Links. These links use the SAAL protocol to

provide an alternative to 56Kbps SS7 links that is based on newer,

    faster technology.  These links implement the SS7 protocol as
    defined in [8].
  • E1 Links.
    Figure 1 provides an overview of the traditional PSTN network.  In
    this network, any of the links can be implemented via either 56
    Kbps, DS1, or E1 links.

Sprague, et al. Informational [Page 7] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

                               ^
                              / \
                             /SCP\
                            /-----\
                              /  \
                             /    \
                            /      \
                           /        \
             /---\      +---+    +---+      /---\
            | SSP |-----|STP|----|STP|-----| SSP |
             \---/  \  /+-+-+\  /+-+-+ \  / \---/
                     \/   |   \/   |    \/
                     /\   |   /\   |    /\
             /---\  /  \+-+-+/  \+-+-+ /  \ /---\
            | SSP |/----|STP|----|STP|/----| SSP |
             \---/      +---+    +---+      \---/
                         \           /
                          \         /
                           \       /
                            \  ^  /
                             \/ \/
                             /SCP\
                            /-----\
            Figure 1: The Traditional PSTN Network

2.2 Converged SS7 Networks

 In the converged SS7 network, SS7 devices will reside on both the
 traditional PSTN network (with dedicated 56 Kbps and DS1 links) and
 on the IP network (with Ethernet links based on IP protocol).  The
 services of SSPs, STPs, and SCPs can be provided by new types of
 devices that reside on IP networks.  The IP network is not intended
 to completely replace the PSTN, rather devices on the 2 types of
 networks must be able to communicate with one another and convert
 from 1 lower layer protocol to the other.
 Signaling Gateways are new devices that may also function as an STP
 in the converged network.  SGs provide interfaces to:
  • devices on the SCN (traditional SSPs, STPs, and SCPs)
  • other SGs
  • new devices on the IP network
 SGs also continue to perform STP functions such as SS7 network
 management and some database services (such as GTT and LNP).

Sprague, et al. Informational [Page 8] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

 New devices on the IP network include:
  • Media Gateway Controllers. In addition to other functions, these

devices control Media Gateways and perform call processing.

  • Media Gateways. In addition to other functions, these devices

control voice circuits that are used to carry telephone calls.

    MGs + MGCs combine to provide the functionality of traditional
    SSPs.
  • IP based SCPs. The database services that are related to SS7 can

be moved onto devices on the IP network.

    Figure 2 provides an overview of the converged SS7 network.
  1. —- +—-+

/\ / \————-| SG |

             /  \----|  SCN  |     +----+ +----+
            /SCP \    \     /------| SG |  |
            ------     -----       +----+  |
                       |   |           |   |
                       |   |           |   |
                       |   |           -----
                       |   |          /     \      /\
                       |   |         |  IP   |----/  \
                       |  /---\       \     /    /SCP \
                       | | SSP |       -----     ------
                       |  \---/         /   \
                       |     |         /     \
                     /---\   |        /       \
                    | SSP |  |     +---+    +---+
                     \---/ +----+  |MGC|    |MGC|
                       |   | MG |  +---+    +---+
                       |   +----+\    \     /
                       |          \    \   /
                       |           \   -----
                       |            \ /     \
                     +----+          |  IP   |
                     | MG |-----------\     /
                     +----+            -----
                  Figure 2: The Converged SS7 Network
 In theory, the TALI protocol can be used between 2 nodes to carry SS7
 traffic across TCP/IP.  Some of the areas that TALI could be used
 include:

Sprague, et al. Informational [Page 9] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

  1. For SG to SG communication across IP
  2. For SG to MGC communication across IP
  3. For SG to IP based SCP communication across IP
  4. For communication between multiple IP based SCPs
  5. For communication between multiple MGCs
  6. For communication between MGCs and MGs
  7. For other IP devices such as DNS, Policy Servers, etc.
 In reality, the communication between MGCs, or between MGC and MG is
 probably better suited to using other protocols.  With respect to the
 Signaling Gateway implementation, the TALI protocol is used to carry
 SS7 traffic:
  1. For SG to SG communication
  2. For SG to MGC communication
  3. For SG to IP based SCP communication

2.3 TALI Protocol Stack Overview

 The Transport Adapter Layer Interface is the proposed interface that
 provides SCCP, ISUP, and MTP messaging encapsulation within a TCP/IP
 packet between two switching elements.  In addition, TALI provides
 SCCP Management (SCMG), MTP Primitives, dynamic registration of
 circuits, and routing of call control messages based on circuit
 location.
 The major purpose of the TALI protocol is to provide a bridge between
 the SS7 Signaling Network and applications that reside within an IP
 network.  Figure 3 provides a simple illustration that highlights the
 protocol stacks used for transport of SS7 MSUs on both the SS7 side
 and the IP side of the SG.

Sprague, et al. Informational [Page 10] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

               SS7 traffic       SS7 traffic
            via 56Kbps links     via TALI
     +-----------+        +----+          +--------+
     |Traditional|        | SG |          |   IP   |
     |SS7 Devices|<------>|    |<-------->| Devices|
     +-----------+        +----+          +--------+
        SS7                          SS7, TALI, TCP/IP
        protocol stack               protocol stack
      +---------------+              +---------------+
      |SS7 application|              |SS7 application|
      |layer          |              |layer          |
      +-------+-------+              +-------+-------+
      | TCAP  | ISUP  |              | TCAP  | ISUP  |
      +-------+       |              +-------+       |
      | SCCP  |       |              | SCCP  |       |
      +-------+-------+              +-------+-------+
      |    MTP3       |              |    MTP3       |
      +---------------+              +---------------+
      |    MTP2       |              |    TALI       |
      +---------------+              +---------------+
      |    MTP1       |              |    TCP        |
      |   (& phy.     |              +---------------+
      |    layer)     |              |    IP         |
      +---------------+              +---------------+
                                     |    MAC        |
                                     |   (& phy.     |
                                     |    layer)     |
                                     +---------------+
     Figure 3: TALI Protocol to carry SS7 over TCP/IP
 From Figure 3, several observations can be made:
  • The TALI layer is used when transferring SS7 over IP.
  • When SS7 traffic is carried over a IP network, the MTP2 and MTP1

layers of a traditional 56 Kbps link are replaced by the TALI,

    TCP, IP, and MAC layers
  • The TALI layer sits on top of the TCP layer.
  • The TALI layer sits below the various SS7 layers (MTP3, SCCP/TCAP,

ISUP, and applications). The data from these SS7 layers is

    carried as the data portion of TALI service data packets.

Sprague, et al. Informational [Page 11] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

 Some of the facts concerning the TALI protocol which are important to
 understanding how TALI works that are not evident from Figure 3
 include the following:
  • Each TALI connection is provided over a single TCP socket.
  • The standard Berkeley sockets interface to the TCP is used by

the TALI layer to provide connection oriented service from

       endpoint to peer endpoint.
  • TCP sockets are based on a Client/Server architecture; one end

of the TALI connection must be defined as the 'server side',

       the other end is a 'client'.
  • The client/server roles are important only in bringing up the

TCP connection between the 2 endpoint, once the connection is

       established both ends use the same Berkeley sockets calls
       (send, recv) to transfer data.
  • The TCP socket must be connected before the 2 TALI endpoints

can begin communicating.

  • TALI provides user control over each TALI connection that is

defined. This control:

  • Allows the user to control when each TALI connection will be

made

  • Allows the user to control when each TALI connection is allowed

to carry SS7 traffic

  • Allows the user to control the graceful shutdown of each socket
  • TALI provides Peer to Peer messages. These messages originate

from the TALI layer of one endpoint of the connection and are

    terminated at the TALI layer of the other endpoint.  Peer to Peer
    messages are used:
  • To provide test and watchdog maintenance messages
  • To control the ability of each socket to carry SS7 service

messages

  • TALI provides Service messages. These messages originate from the

layer above the TALI layer of one endpoint of the connection and

    are transferred to and terminated at the layer above the TALI
    layer of the other endpoint.

Sprague, et al. Informational [Page 12] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

  • The service messages provide several different ways to

encapsulate the SS7 messages (SCCP/TCAP, ISUP, and other MTP3

       layer data) across the TCP/IP connection.
  • As we will see later, different Service opcodes are used to

communicate across the TALI socket exactly how each SS7 message

       has been encapsulated.
  • A set of TALI timers is defined. These timers are used to

correctly implement the TALI state machine.

2.3.1 An Alternate TALI Protocol Stack using the SAAL Layer

 This section presents a different, slightly more complex, TALI
 protocol stack that can be used in place of the protocol stack in the
 previous section.
 Figure 3 in the previous section provided a simple illustration that
 highlighted the basic TALI protocol stack that can be used to
 transport SS7 MSUs between 56 Kbps links on the SS7 side of an SG and
 the IP devices.
 Figure 4 below illustrates an alternate TALI protocol stack that
 includes the SAAL layer as part of the data transferred across the
 TCP/IP connection.

Sprague, et al. Informational [Page 13] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

                  SS7 traffic       SS7 traffic
                  via DS1 links     via TALI
        +-----------+        +----+          +--------+
        |Traditional|        | SG |          |   IP   |
        |SS7 Devices|<------>|    |<-------->| Devices|
        +-----------+        +----+          +--------+
           SS7 DS1                   SS7, TALI, TCP/IP
           protocol stack            protocol stack
         +-----------------+        +-----------------+
         | SS7 application |        | SS7 application |
         | layer           |        | layer           |
         +--------+--------+        +--------+--------+
         |  TCAP  | ISUP   |        |  TCAP  | ISUP   |
         +--------+        |        +--------+        |
         |  SCCP  |        |        |  SCCP  |        |
         +--------+--------+        +--------+--------+
         |      MTP3       |        |      MTP3       |
         +-----------------+        +-----------------+
         |    SAAL         |        |     SAAL        |
         |(SSCF,MAAL,SSCOP)|        |(SSCF,MAAL,SSCOP)|
         +-----------------+        +-----------------+
         |     AAL5        |        |     TALI        |
         +-----------------+        +-----------------+
         |     ATM         |        |     TCP         |
         |    (& phy.      |        +-----------------+
         |     layer)      |        |     IP          |
         +-----------------+        +-----------------+
                                    |     MAC         |
                                    |    (& phy.      |
                                    |     layer)      |
                                    +-----------------+
      Figure 4: An Alternate TALI Protocol Stack with SAAL
 The following bullets provide a discussion regarding the differences
 between these 2 protocol stacks, the reasons for having 2 protocol
 stacks, and the advantages of each:
  • When the TALI protocol stack is implemented without the SAAL

layer, as in Figure 3, the SEQUENCE NUMBER of the SS7 MSU is NOT

    part of the data transferred across the TCP/IP connection.  In 56
    Kbps SS7 links, the MTP2 header contains an 8 bit sequence number
    for each MSU.  The sequence number is used to preserve message
    sequencing and to support complex SS7 procedures involving MSU
    retrieval during link changeover and changeback.  As indicated in
    Figure 3, the MTP2 header is NOT part of the data transferred

Sprague, et al. Informational [Page 14] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

    across the TCP/IP connection.  The TALI protocol stack without
    SAAL still guarantees correct sequencing of SS7 data (this
    sequencing is provided by sequence numbers in the TCP layer),
    however that protocol stack can not support SS7 changeover and
    changeback procedures.
  • When the TALI protocol stack is implemented with the SAAL layer,

as in Figure 4, the SEQUENCE NUMBER of the SS7 MSU IS part of the

    data transferred across TCP/IP.  In SS7 DS1 links, the SSCOP
    trailer contains a 24 bit sequence number for each MSU.  This 24
    bit sequence number serves the same purposes as the 8 bit SS7
    sequence number.  As indicated in Figure 4, the SSCOP trailer IS
    part of the data transferred across the TCP/IP connection.  The
    protocol stack in Figure 4 can support SS7 changeover and
    changeback procedures.
  • Implementing the TALI protocol with SAAL therefore provides

support for SS7 co/cb and data retrieval and can help to minimize

    MSU loss as SS7 links are deactivated.  However, implementing SAAL
    is not a trivial matter.  The SAAL layer consists of 3 sublayers
    (SSCF, SSCOP, and MAAL), one of which (SSCOP) is quite involved.
    It is envisioned that most SS7 to TCP/IP applications will NOT
    choose to implement SAAL.

2.3.2 An Alternate TALI Protocol Stack using SCTP

 The TALI protocol is dependent on a reliable transport layer below
 it.  At the initial design of TALI, TCP was the only reliable, proven
 transport layer.  Simple Control Transport Protocol (SCTP) is
 currently being designed as a transport later specifically for
 signalling.  Once SCTP is a proven and accepted transport protocol,
 SCTP can then be used in place of TCP as shown in Figures 3 and 4.

2.4 Inputs to the TALI Version 1.0 State Machine

 Figure 5 illustrates the inputs that affect the TALI State Machine.
 Inputs to the state machine include:
  • Management events (ie: requests from the human user of the TALI

connection) to control the operation of a particular TALI session.

  • TALI messages received from the Peer. These messages include peer

to peer messages as well as service data messages.

  • Events from the User of the TALI layer. The user is the layer

above TALI in the protocol stack, either the SS7 or SAAL layer.

Sprague, et al. Informational [Page 15] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

  • Implementation Dependent Events. Each implementation must provide

inputs into the TALI state machine such as:

  • Socket Events
  • TALI protocol violations. The TALI state machine must detect

protocol violations and act accordingly.

  • Timer events.

Sprague, et al. Informational [Page 16] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

    +====+                                   +============+
    |    |    +---------+ +-------------+    |            |
    |User|    | Service | | Mgmt. Open  |    | MANAGEMENT |
    |Part|<-->| Message | | Mgmt. Close |<-->|            |
    |    |    |         | | Mgmt. Proh. |    |            |
    |    |    +---------+ | Mgmt. Allow |    +============+
    +====+          ^     +-------------+
                    |            ^
                    |            |
                    v            v
    +========================================================+
    |                 TALI State Machine                     |
    +========================================================+
          ^               ^                 ^             ^
          |               |                 |             |
          |               |                 |             |
          v               |                 |             |
     +---------+  +-----------------+ +-----------+ +------------+
     | Received|  | Connection est. | | Protocol  | | T1 Expired |
     | 'test'  |  | Connection lost | | Violation | | T2 Expired |
     | 'allo'  |  |                 | |           | | T3 Expired |
     | 'proh'  |  +-----------------+ +-----------+ | T4 Expired |
     | 'proa'  |          ^                 ^       +------------+
     | 'moni'  |          |                 |              ^
     | 'mona'  |          |                 |              |
     |    or   |          |                 |              |
     | Service |          |                 |              |
     | Message |    +========================================+
     +---------+    |         IMPLEMENTATION                 |
          ^         |           DEPENDENT                    |
          |         +========================================+
          |
          v
      +============+
      |    PEER    |
      |            |
      +============+
    Figure 5: Overview of Inputs to the TALI 1.0 State Machine

Sprague, et al. Informational [Page 17] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

3. TALI Version 1.0

 This chapter provides the states, messages, message exchange rules
 and state machine that must be implemented to provide a TALI version
 1.0 protocol layer.

3.1 Overview of the TALI Message Structure

 Table 2 provides a summary of the messages and message structure used
 in TALI version 1.0.
 +------------------------------------------------------------------+
 | OCTET | DESCRIPTION              | SIZE     | VALUE  |    TYPE   |
 +------------------------------------------------------------------+
 | 0..3  | SYNC                     | 4 Octets |        | 4 byte    |
 |       |                          |          |        | ASCII     |
 +------------------------------------------------------------------+
 |       |   TALI                   |          | 'TALI' |           |
 +------------------------------------------------------------------+
 | 4..7  | OPCODE                   | 4 Octets |        | 4 byte    |
 |       |                          |          |        | ASCII     |
 +------------------------------------------------------------------+
 |       |   Test Service           |          | 'test' |           |
 |       |   Allow Service          |          | 'allo' |           |
 |       |   Prohibit Service       |          | 'proh' |           |
 |       |   Prohibit Service Ack   |          | 'proa' |           |
 |       |   Monitor Socket         |          | 'moni' |           |
 |       |   Monitor Socket Ack     |          | 'mona' |           |
 |       |   SCCP Service           |          | 'sccp' |           |
 |       |   ISUP Service over TALI |          | 'isot' |           |
 |       |   MTP3 Service over TALI |          | 'mtp3' |           |
 |       |   Service over SAAL      |          | 'saal' |           |
 +------------------------------------------------------------------+
 | 8..9  | LENGTH                   | 2 Octets |        | integer   |
 |       |   (least significant     |          |        |           |
 |       |    byte first) non-0     |          |        |           |
 |       |    if Service or         |          |        |           |
 |       |    Socket monitor message|          |        |           |
 +------------------------------------------------------------------+
 | 10..X | DATA PAYLOAD             | variable |        | variable  |
 +------------------------------------------------------------------+
               Table 2: Message Structure for TALI 1.0
 Table 3 indicates the valid values of the LENGTH field for each
 version 1.0 opcode.  The LENGTH field is always an indication of the
 # of bytes contained in the DATA PAYLOAD portion of a general TALI
 message.

Sprague, et al. Informational [Page 18] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

 +------------------------------------------------------------------+
 | OPCODE | VALID LENGTH VALUES | COMMENTS                          |
 +------------------------------------------------------------------+
 | test   | 0 bytes             |                                   |
 +------------------------------------------------------------------+
 | allo   | 0 bytes             |                                   |
 +------------------------------------------------------------------+
 | proh   | 0 bytes             |                                   |
 +------------------------------------------------------------------+
 | proa   | 0 bytes             |                                   |
 +------------------------------------------------------------------+
 | moni   | 0-200 bytes         | A maximum length is provided so   |
 |        |                     | that the maximum ethernet frame   |
 |        |                     | size is not exceeded.             |
 +------------------------------------------------------------------+
 | mona   | 0-200 bytes         | Mona reply length and content must|
 |        |                     | match the original moni (with the |
 |        |                     | exception of the opcode)          |
 +------------------------------------------------------------------+
 | sccp   | 12-265 bytes        | These are the valid sizes for the |
 |        |                     | SCCP-ONLY portions of SCCP UDT    |
 |        |                     | MSUs                              |
 +------------------------------------------------------------------+
 | isot   | 8-273 bytes         | The length is the number of octets|
 |        |                     | in the MTP3 and higher layer(s) of|
 |        |                     | the SS7 MSU.  This length includes|
 |        |                     | the SIO byte, the MTP3 routing    |
 |        |                     | label, the CIC code, and the      |
 |        |                     | ISUP Message Type field, and any  |
 |        |                     | other bytes that may exist as part|
 |        |                     | of the SIF (Service Information   |
 |        |                     | Field)                            |
 +------------------------------------------------------------------+
 | mtp3   | 5-280 bytes         | The length is the number of octets|
 |        |                     | in the MTP3 and higher layer(s) of|
 |        |                     | the SS7 MSU.  This length includes|
 |        |                     | the SIO byte and the MTP3 routing |
 |        |                     | labeld, and any other bytes that  |
 |        |                     | may exist as part of the SIF      |
 |        |                     | (Service Information Field)       |
 +------------------------------------------------------------------+
 | saal   | 11-280 bytes        | The length is the number of octets|
 |        |                     | in the MTP3 and higher layer(s) of|
 |        |                     | the SS7 MSU.  This length includes|
 |        |                     | the SIO byte and all bytes in the |
 |        |                     | SIF (Service Information Field)   |
 |        |                     | field.  The MTP3 routing label is |
 |        |                     | part of the SIF field.  Seven (7) |

Sprague, et al. Informational [Page 19] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

 |        |                     | octets of SSCOP trailer is added  |
 |        |                     | to the message.  The SSCOP trailer|
 |        |                     | bytes are also included in the    |
 |        |                     | length.                           |
 +------------------------------------------------------------------+
      Table 3: Valid Length Fields for Each Opcode in TALI 1.0

3.1.1 Types of TALI Fields

 Several field types are used in the general TALI message structure.
 +------------------------------------------------------------------+
 |Field Type | Implementation Notes for that Type                   |
 +------------------------------------------------------------------+
 |4 byte     | * 4 byte ASCII text strings are used to define the   |
 |ASCII text |   sync code and the opcode of the basic TALI message.|
 |           | * These fields are case sensitive, the coding for    |
 |           |   each sync and opcode literal needs to match the    |
 |           |   case specified in Table 2.                         |
 |           | * The standard ASCII conversion table is used to     |
 |           |   transform each character into a byte.              |
 |           | * The order of the ASCII characters is important.    |
 |           |   The first character in the string must be the      |
 |           |   first character transmitted across the wire.       |
 |           | * For example, if the string being encoded is 'abCD',|
 |           |   the order of the bytes as they are transferred     |
 |           |   over the wire must be:                             |
 |           |     1st byte: 0x61 ('a')  3rd byte: 0x43 ('C')       |
 |           |     2nd byte: 0x62 ('b')  4th byte: 0x44 ('D')       |
 |           | * The software for each implementation should be     |
 |           |   written in a manner that accounts for the required |
 |           |   byte order of transmission (ie: the Big Endian/    |
 |           |   Little Endian characteristics of the processor     |
 |           |   need to be dealt with in the software.             |
 +------------------------------------------------------------------+
 |Integer    | * A 1, 2 or 4 byte field to be treated as an integer |
 |           |   value.  Integer fields should be transmitted Least |
 |           |   Significant Byte first across the wire.            |
 |           | * The software for each implementation should be     |
 |           |   written in a manner that accounts for the required |
 |           |   byte order of transmission (ie: the Big Endian/    |
 |           |   Little Endian characteristics of the processor     |
 |           |   need to be dealt with in the software.             |
 +------------------------------------------------------------------+
 |Variable   | * The definition of the message structure for this   |
 |           |   field is governed by other specifications.         |
 |           | * For example, when transferring MTP3 service data   |

Sprague, et al. Informational [Page 20] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

 |           |   via a 'mtp3' opcode, the DATA PAYLOAD begins with  |
 |           |   the SIO byte of the MTP3 routing label.  The       |
 |           |   structure for the entire DATA PAYLOAD is governed  |
 |           |   by the MTP3 message structure defined in [1].      |
 +------------------------------------------------------------------+
 |X byte     | * ASCII text fields of sizes other than 4 bytes      |
 |ASCII text |   should be supported according to the same rules    |
 |           |   presented for the 4 byte ASCII text fields.  For   |
 |           |   instance, an 8 byte string such as 'ab01cd23' could|
 |           |   be used, where the 'a' would be the first byte of  |
 |           |   the field transmitted out the wire.                |
 +------------------------------------------------------------------+
       Table 4: Implementation Notes for each Type of TALI field

3.2 Detailed TALI Message Structure

3.2.1 TALI Peer to Peer Messages

 The following subsections provide more information regarding the TALI
 Peer to Peer messages that are implemented in version 1.0.  The TALI
 peer to peer messages originate at the TALI layer of 1 end of the
 socket connection (the near end) and are terminated at the TALI layer
 of the far end of the connection.

3.2.1.1 Test Message (test)

 The 'test' message is used by a TALI implementation to query the
 remote end of the TALI connection with respect to the willingness of
 the remote end to carry SS7 service data.  This message asks the
 other end: are you ready to carry service data?  This message is sent
 periodically by each TALI implementation based on a T1 timer
 interval.  Upon receiving 'test', a TALI implementation must reply
 with either 'proh' or 'allo' to indicate the nodes willingness to
 carry SS7 service data over that TALI connection.
 +------------------------------------------------------------------+
 | Octets | Field Name  | Description                               |
 +------------------------------------------------------------------+
 | 0..3   | SYNC        | 'TALI'                                    |
 +------------------------------------------------------------------+
 | 4..7   | OPCODE      | 'test'                                    |
 +------------------------------------------------------------------+
 | 8..9   | LENGTH      | Length = 0                                |
 +------------------------------------------------------------------+

Sprague, et al. Informational [Page 21] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

3.2.1.2 Allow Message (allo)

 The 'allo' message is sent in reply to a 'test' query, or in response
 to some internal implementation event, to indicate that a TALI
 implementation IS willing to carry SS7 service data over the TALI
 session.  This message informs the far end that SS7 traffic can be
 transmitted on the socket.  'allo' is one of the 2 possible replies
 to a 'test' message.  Before SS7 traffic can be carried over a
 socket, both ends of the connection need to send 'allo' messages.
 +------------------------------------------------------------------+
 | Octets | Field Name  | Description                               |
 +------------------------------------------------------------------+
 | 0..3   | SYNC        | 'TALI'                                    |
 +------------------------------------------------------------------+
 | 4..7   | OPCODE      | 'allo'                                    |
 +------------------------------------------------------------------+
 | 8..9   | LENGTH      | Length = 0                                |
 +------------------------------------------------------------------+

3.2.1.3 Prohibit Message (proh)

 The 'proh' message is sent in reply to a 'test' query, or in response
 to some internal implementation event, to indicate that a TALI
 implementation is NOT willing to carry SS7 service data over the TALI
 session.  This message informs the far end that SS7 traffic can not
 be transmitted on the socket.  'proh' is one of the 2 possible
 replies to a 'test' message.  As long as 1 end of the connection
 remains in the 'prohibited' state, SS7 traffic can not be carried
 over the socket.
 +------------------------------------------------------------------+
 | Octets | Field Name  | Description                               |
 +------------------------------------------------------------------+
 | 0..3   | SYNC        | 'TALI'                                    |
 +------------------------------------------------------------------+
 | 4..7   | OPCODE      | 'proh'                                    |
 +------------------------------------------------------------------+
 | 8..9   | LENGTH      | Length = 0                                |
 +------------------------------------------------------------------+

3.2.1.4 Prohibit Acknowledgement Message (proa)

 The 'proa' message is sent by a TALI implementation each time a
 'proh' is received from the far end.  This message is sent to
 indicate to the far end that his 'prohibit' message was received
 correctly and will be acted on accordingly.

Sprague, et al. Informational [Page 22] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

 +------------------------------------------------------------------+
 | Octets | Field Name  | Description                               |
 +------------------------------------------------------------------+
 | 0..3   | SYNC        | 'TALI'                                    |
 +------------------------------------------------------------------+
 | 4..7   | OPCODE      | 'proa'                                    |
 +------------------------------------------------------------------+
 | 8..9   | LENGTH      | Length = 0                                |
 +------------------------------------------------------------------+

3.2.1.5 Monitor Message (moni)

 The 'moni' message provides a generic ECHO capability that can be
 used by each TALI implementation as that implementation sees fit.  A
 TALI version 1.0 implementation does not have to originate a 'moni'
 message to be compliant with the 1.0 specification.  The primary
 intent of this message is to provide a way for the TALI layer to test
 the round-trip message transfer time on a socket.  A 'mona' message
 must be sent in reply to each received 'moni' message.  The DATA
 portion of a 'moni' message is vendor implementation dependent.  The
 DATA portion of each 'mona' reply must exactly match the DATA portion
 of the 'moni' that is replied to.  Regardless of whether an
 implementation chooses to send 'moni' or not, 'mona' must be sent in
 response to each 'moni' in order to remain compliant with the TALI
 protocol.
 +------------------------------------------------------------------+
 | Octets | Field Name  | Description                               |
 +------------------------------------------------------------------+
 | 0..3   | SYNC        | 'TALI'                                    |
 +------------------------------------------------------------------+
 | 4..7   | OPCODE      | 'moni'                                    |
 +------------------------------------------------------------------+
 | 8..9   | LENGTH      | Length                                    |
 +------------------------------------------------------------------+
 | 10..X  | DATA PAYLOAD| Vendor Dependent                          |
 +------------------------------------------------------------------+

3.2.1.6 Monitor Acknowledge Message (mona)

 As mentioned above, the 'mona' must be sent in reply to each received
 'moni'.  The contents of the 'mona' DATA area must match the DATA
 area of the received 'moni' message.

Sprague, et al. Informational [Page 23] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

 +------------------------------------------------------------------+
 | Octets | Field Name  | Description                               |
 +------------------------------------------------------------------+
 | 0..3   | SYNC        | 'TALI'                                    |
 +------------------------------------------------------------------+
 | 4..7   | OPCODE      | 'mona'                                    |
 +------------------------------------------------------------------+
 | 8..9   | LENGTH      | Length                                    |
 +------------------------------------------------------------------+
 | 10..X  | DATA PAYLOAD| Vendor Dependent                          |
 +------------------------------------------------------------------+

3.2.2 Service Messages

 The following subsections provide more information regarding the TALI
 Service messages that are implemented in version 1.0.  TALI Service
 messages are used to carry SS7 MSUs across the IP network.  The
 information in this section includes details with respect to how to
 encapsulate SS7 MSUs into TCP/IP frames using each of the TALI
 service opcodes.  The TALI service messages originate at the layer
 above TALI, are transported across the IP network via a TALI service
 message, and are delivered to the layer above TALI at the far end of
 the TALI connection.

3.2.2.1 SCCP Service Message (sccp)

 The 'sccp' opcode is used to deliver SS7 MSUs with a Service
 Indicator of 3 (SCCP) over a TALI connection.  This opcode is only
 used on TALI protocol stacks that are implemented without SAAL.  The
 MTP3 layer of the SS7 MSU is NOT part of the data transferred across
 TCP/IP for this opcode; the data portion of the TALI 'sccp' message
 begins with the first byte of the SCCP data area in the SS7 MSU
 (after the MTP3 routing label).  The first byte in the SCCP data area
 is an SCCP message type field.
 Several restrictions on the SCCP messages that this TALI opcode can
 carry exist.  These restrictions are as follows:
  • SCCP messages contain an SCCP message type field. The SCCP

messages that are supported by TALI 1.0 implementations are

    limited to Class 0 and Class 1 SCCP messages with a message type
    field of either:
  • UDT
  • UDTS
  • XUDT
  • XUDTS

Sprague, et al. Informational [Page 24] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

  • SCCP messages must contain a Point Code in the 'calling party'

area in order to be transferred across the TCP/IP connection as a

    'sccp' message.  An implementation may choose to modify the
    original SCCP MSU to add an appropriate calling party point code
    before transmission across TALI if desired.
  • SCCP messages must contain a Point Code in the 'called party' area

in order to be transferred across the TCP/IP connection as a

    'sccp' message.  An implementation may choose to modify the
    original SCCP MSU to add an appropriate called party point code
    before transmission across TALI if desired.
  • The encoding of the SS7 SCCP MSUs, as they are transmitted across

TALI via 'sccp', should remain compliant with the ANSI

    specifications (T1.112 and T1.114) that apply to the SCCP and TCAP
    portions of the message respectively.
 NOTE 1: SCCP Subsystem Management for the IP based SCP's is supported
 via this 'sccp' opcode.  SS7 SCCP Management messages are controlled
 by an SCMG SS7 process.  SCMG sends the management messages via SCCP
 UNITDATA (UDT) messages.  Therefore, the SCMG messages can be sent
 across the TALI connection.
 NOTE 2: 'sccp' TALI messages will not include the MTP3 header and
 therefore will not retain the original DPC/OPC of the SS7 MSU.  Each
 TALI implementation needs to consider if/how to provide this DPC/OPC
 information in the SCCP portion of the message.  For example the DPC
 can be replicated to the point code in the SCCP Called Party Address
 area and the OPC can be replicated to the point code in the SCCP
 Calling Party Address area.
 +------------------------------------------------------------------+
 | Octets | Field Name  | Description                               |
 +------------------------------------------------------------------+
 | 0..3   | SYNC        | 'TALI'                                    |
 +------------------------------------------------------------------+
 | 4..7   | OPCODE      | 'sccp'                                    |
 +------------------------------------------------------------------+
 | 8..9   | LENGTH      | Length                                    |
 +------------------------------------------------------------------+
 | 10..X  | SCCP Data   | SCCP data starting at the first byte after|
 |        |             | the Layer 3 Routing Label (data does not  |
 |        |             | include the SIO or Routing Label)         |
 +------------------------------------------------------------------+

Sprague, et al. Informational [Page 25] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

3.2.2.1.1 SCCP Encapsulation using TALI

 When an SCCP MSU arrives at an SG from a 56 Kbps or DS1 link and is
 routed within the SG for transmission to an IP device, the SG
 performs the following processing on the SS7 MSU:
  • discards the MTP Layer 2 information, CRC and flags
  • places the DPC from MTP Layer 3 into the Called Party Address

field of the SCCP layer; the Calling Party Address field is

    created if it does not exist and then filled
  • places the OPC from MTP Layer 3 into the Calling Party Address

field of the SCCP layer if there is no Calling Party Point Code

  • places the modified SCCP and unchanged TCAP data in the service

payload area of the TALI packet

  • The SYNC field is set
  • The OPCODE is set to 'sccp'
  • The LENGTH is set to the number of octets in the SERVICE field
 Once the fully formed 'sccp' TALI packet is created, it is handed to
 the TCP socket layer and transmitted.  The transmission process will
 add TCP, IP and MAC header information.
 Since the routing information from MTP Layer 3 is placed in the SCCP
 part of the outgoing message, no routing information needs to be
 saved by the SG.

Sprague, et al. Informational [Page 26] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

                              SS7 MSU
         |          Layer 3          |     Layer 2      |
         |                           |                  |
    +----+---+-----+-----+-------+---+--+---+---+---+---+----+
    |Flag|FCS|TCAP |SCCP |Routing|SIO|LI|FIB|FSN|BIB|BSN|Flag|
    |    |   |Layer|Layer| Label |   |  |   |   |   |   |    |
    +----+---+-----+-----+-------+---+--+---+---+---+---+----+
             |           |
             |           |
             |           |
      TALI   +-----------+---+------+----+
      Packet |  Service  |LEN|Opcode|SYNC|
             +-----------+---+------+----+
             |                           |
             |                           |
             |                           |
             +---------------------------+------+------+------+
      IP     | TALI Packet               |TCP   | IP   | MAC  |
      Packet |                           |Header|Header|Header|
             +---------------------------+------+------+------+
 Figure 6: Encapsulation of SCCP MSUs using the TALI 'sccp' opcode
 When an 'sccp' TALI packet is received on by an SG from an IP device,
 the SG performs the following processing on the 'sccp' packet:
  • validates the TALI header
  • Allocates space for a new SS7 message
  • Regenerates the SIO with the Sub-Service Field set to National

Network, priority of zero (0), Service Indicator set to SCCP

  • extracts the SCCP/TCAP data from the SERVICE area and places it in

the new SS7 message

  • sets the DPC to the SCCP Called Party Point Code
  • sets the OPC to the SCCP Calling Party Point Code
  • randomly generates the SLS
 Once the 'sccp' packet is transformed back into a normal SS7 MSU, the
 MSU is routed within the SG according to the normal SS7 routing
 procedures.

Sprague, et al. Informational [Page 27] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

3.2.2.2 ISUP Service Message (isot)

 The 'isot' opcode is used to deliver SS7 MSUs with a Service
 Indicator of 5 (ISUP) over a TALI connection.  This opcode is only
 used on TALI protocol stacks that are implemented without SAAL.  The
 MTP3 layer of the SS7 MSU IS part of the data transferred across
 TCP/IP for this opcode; the data portion of the TALI 'isot' message
 begins with the SIO byte of the MTP3 header in the SS7 MSU.
 +------------------------------------------------------------------+
 | Octets | Field Name  | Description                               |
 +------------------------------------------------------------------+
 | 0..3   | SYNC        | 'TALI'                                    |
 +------------------------------------------------------------------+
 | 4..7   | OPCODE      | 'isot'                                    |
 +------------------------------------------------------------------+
 | 8..9   | LENGTH      | Length                                    |
 +------------------------------------------------------------------+
 | 10..X  | ISUP Data   | Raw ISUP data starting at the Layer 3 SIO |
 |        |             | field.                                    |
 +------------------------------------------------------------------+

3.2.2.2.1 ISUP Encapsulation using TALI

 When an ISUP MSU arrives at an SG from a 56 Kbps or DS1 link and is
 routed within the SG to a IP device, the SG performs the following
 processing on the SS7 MSU:
  • discards the MTP Layer 2 information, CRC and flags
  • places MTP Layer 3 into the SERVICE payload area of the TALI

packet

  • The SYNC field is set
  • The OPCODE is set to 'isot'
  • The LENGTH is set to the number of octets in the SERVICE field
 Once the fully formed 'isot' TALI packet is created, it is handed to
 the TCP socket layer and transmitted.  The transmission process will
 add TCP, IP and MAC header information.
 Since the routing information is placed in the TALI Packet, no
 routing information needs to be saved by the SG.

Sprague, et al. Informational [Page 28] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

                            SS7 MSU
         |          Layer 3            |     Layer 2      |
         |                             |                  |
    +----+---+----+----+---+-------+---+--+---+---+---+---+----+
    |Flag|FCS|ISUP|Msg.|CIC|Routing|SIO|LI|FIB|FSN|BIB|BSN|Flag|
    |    |   |Part|Type|   |Label  |   |  |   |   |   |   |    |
    +----+---+----+----+---+-------+---+--+---+---+---+---+----+
             |                         /
             |                        /
             |                       |
      TALI   +-----------------------+---+------+----+
      Packet |  Service              |LEN|Opcode|SYNC|
             +-----------------------+---+------+----+
             |                                       /
             |                              ---------
             |                             /
             +----------------------------+------+------+------+
      IP     | TALI Packet                |TCP   | IP   | MAC  |
      Packet |                            |Header|Header|Header|
             +----------------------------+------+------+------+
   Figure 7: Encapsulation of ISUP MSUs using the TALI 'isot' opcode
 When an 'isot' TALI packet is received on an SG from an IP device,
 the SG performs the following processing on the 'isot' packet:
  • validates the TALI header
  • Allocates space for a new SS7 message
  • extracts the MTP Layer 3 data from the SERVICE area and places it

in the new SS7 message

 Once the 'isot' packet is transformed back into a normal SS7 MSU, the
 MSU is routed within the SG according to the normal SS7 routing
 procedures.

3.2.2.3 MTP3 Service Message (mtp3)

 The 'mtp3' opcode is used to deliver SS7 MSUs with a Service
 Indicator of 0-2, 4, 6-15 (non-SCCP, non-ISUP) over a TALI
 connection.  This opcode is only used on TALI protocol stacks that
 are implemented without SAAL.  The MTP3 layer of the SS7 MSU IS part
 of the data transferred across TCP/IP for this opcode; the data
 portion of the TALI 'mtp3' message begins with the SIO byte of the
 MTP3 header in the SS7 MSU.

Sprague, et al. Informational [Page 29] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

 +------------------------------------------------------------------+
 | Octets | Field Name  | Description                               |
 +------------------------------------------------------------------+
 | 0..3   | SYNC        | 'TALI'                                    |
 +------------------------------------------------------------------+
 | 4..7   | OPCODE      | 'mtp3'                                    |
 +------------------------------------------------------------------+
 | 8..9   | LENGTH      | Length                                    |
 +------------------------------------------------------------------+
 | 10..X  | Layer 3 MSU | Raw MSU data starting at the Layer 3 SIO  |
 |        | Data        | field.                                    |
 +------------------------------------------------------------------+

3.2.2.3.1 MTP3 Encapsulation using TALI

 When an SS7 MSU with SI=0-2,4,6-15 arrives at an SG from a 56 Kbps or
 DS1 link and is routed within the SG to an IP device, the SG performs
 the following processing on the SS7 MSU:
  • discards the MTP Layer 2 information, CRC and flags
  • places MTP Layer 3 into the SERVICE payload area of TALI packet
  • The SYNC field is set
  • The OPCODE is set to 'mtp3'
  • The LENGTH is set to the number of octets in the SERVICE field
 Once the fully formed 'mtp3' TALI packet is created, it is handed to
 the TCP socket layer and transmitted.  The transmission process will
 add TCP, IP and MAC header information.

Sprague, et al. Informational [Page 30] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

                           SS7 MSU
         |      Layer 3              |     Layer 2      |
         |                           |                  |
    +----+---+-----------+-------+---+--+---+---+---+---+----+
    |Flag|FCS|Other Layer|Routing|SIO|LI|FIB|FSN|BIB|BSN|Flag|
    |    |   |3 Data     |Label  |   |  |   |   |   |   |    |
    +----+---+-----------+-------+---+--+---+---+---+---+----+
             |                       /
             |                 ------
             |                /
      TALI   +----------------+---+------+----+
      Packet |  Service       |LEN|Opcode|SYNC|
             +----------------+---+------+----+
             |                                /
             |                              --
             |                             /
             +----------------------------+------+------+------+
      IP     | TALI Packet                |TCP   | IP   | MAC  |
      Packet |                            |Header|Header|Header|
             +----------------------------+------+------+------+
    Figure 8: Encapsulation of SS7 MSUs with SI!=3,5,13 using 'mtp3'
 When an 'mtp3' TALI packet is received by an SG from an IP device,
 the SG performs the following processing on the 'mtp3' packet:
  • validates the TALI header
  • Allocates space for a new SS7 message
  • extracts the MTP Layer 3 data from the SERVICE area and places it

in the new SS7 message

 Once the 'mtp3' packet is transformed back into a normal SS7 MSU, the
 MSU is routed within the SG according to the normal SS7 routing
 procedures.

3.2.2.4 SAAL Service Message (saal)

 The 'saal' opcode is used to deliver SS7 MSUs with any Service
 Indicator over a TALI connection.  This opcode is only used on TALI
 protocol stacks that are implemented with SAAL.  The 'saal' opcode is
 also used to transmit SAAL peer to peer packets (SSCF peer to peer
 packets and SSCOP peer to peer packets other than SS7 service data)
 over a TALI connection.

Sprague, et al. Informational [Page 31] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

 When used to transfer SS7 MSUs, the MTP3 layer of the SS7 MSU IS part
 of the data transferred across TCP/IP for this opcode; the data
 portion of the TALI 'saal' message begins with the SIO byte of the
 MTP3 header in the SS7 MSU and ends with the last byte of the SSCOP
 trailer.
 When used to transfer SSCF/SSCOP peer to peer messages the data
 portion of the TALI 'saal' message includes the entire SSCOP PDU.
 +------------------------------------------------------------------+
 | Octets | Field Name  | Description                               |
 +------------------------------------------------------------------+
 | 0..3   | SYNC        | 'TALI'                                    |
 +------------------------------------------------------------------+
 | 4..7   | OPCODE      | 'saal'                                    |
 +------------------------------------------------------------------+
 | 8..9   | LENGTH      | Length                                    |
 +------------------------------------------------------------------+
 | 10..X  | Layer 3     | Raw MSU data starting at the Layer 3 SIO  |
 |        | Data        | field.                                    |
 +------------------------------------------------------------------+
 | (X+1)  | SSCOP       | Zero (0) to three (3) octets of padding   |
 |  ..Y   | Trailer     | plus 4 octets for the trailer data.  The  |
 |        |             | total length of the Layer 3 Data and the  |
 |        |             | SSCOP trailer must be a multiple of 4.    |
 +------------------------------------------------------------------+
                      or
 +------------------------------------------------------------------+
 | Octets | Field Name  | Description                               |
 +------------------------------------------------------------------+
 | 0..3   | SYNC        | 'TALI'                                    |
 +------------------------------------------------------------------+
 | 4..7   | OPCODE      | 'saal'                                    |
 +------------------------------------------------------------------+
 | 8..9   | LENGTH      | Length                                    |
 +------------------------------------------------------------------+
 | 10..X  | SAAL Peer   | Raw SSCF/SSCOP peer to peer packets are   |
 |        | to Peer     | also transferred over the TALI connection |
 |        | message     | using this 'saal' opcode.                 |
 +------------------------------------------------------------------+

3.2.2.4.1 MTP3 and SAAL Peer to Peer Encapsulation using TALI

 When an SS7 MSU (with any SI) arrives at an SG from a 56 Kbps or DS1
 link and is routed within the SG for transmission to an IP device,
 the SG performs the following processing on the SS7 MSU:

Sprague, et al. Informational [Page 32] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

  • discards the MTP Layer 2 information, CRC and flags
  • the MSU is passed from an MTP3 processing software layer to the

SSCF and SSCOP layers (the SAAL layers). These layers convert the

    SS7 MSU into an SSCOP PDU.  Part of this conversion includes
    adding an SSCOP trailer.
  • the SSCOP PDU (whether it is a peer to peer SAAL message or SS7

MSU in an SSCOP PDU) is copied into the SERVICE payload area of

    the TALI packet
  • The SYNC field is set
  • The OPCODE is set to 'saal'
  • The LENGTH is set to the number of octets in the SERVICE field
 Once the fully formed 'saal' TALI packet is created, it is handed to
 the TCP socket layer and transmitted.  The transmission process will
 add TCP, IP and MAC header information.
 Since the routing information is placed in the TALI Packet, no
 routing information needs to be saved by the SG.

Sprague, et al. Informational [Page 33] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

                             SS7 MSU
         |          Layer 3          |     Layer 2      |
         |                           |                  |
    +----+---+-----------+-------+---+--+---+---+---+---+----+
    |Flag|FCS|Other Layer|Routing|SIO|LI|FIB|FSN|BIB|BSN|Flag|
    |    |   |3 Data     |Label  |   |  |   |   |   |   |    |
    +----+---+-----------+-------+---+--+---+---+---+---+----+
             |                       |
             |                       |
             |                       |
     +-------+-----------------------+
     |SSCOP  |  Service              |
     |Trailer|                       |
     +-------+-----------------------+
     |                               |
     +-------+-----------------------+---+------+----+
     |Service with SSCOP Trailer     |LEN|Opcode|SYNC|
     +-------+-----------------------+---+------+----+
     |                                               /
     |                              -----------------
     |                             /
     +----------------------------+------+------+------+
     | TALI Packet                |TCP   | IP   | MAC  |
     |                            |Header|Header|Header|
     +----------------------------+------+------+------+
 Figure 9: Encapsulation of SAAL PDUs using the TALI 'saal' opcode
 When an 'saal' TALI packet is received at the SG from an IP device,
 the SG performs the following processing on the 'saal' packet:
  • validates the TALI header
  • Allocates space for a new SSCOP PDU message
  • extracts the SSCOP PDU data from the SERVICE area and places it in

the new SSCOP PDU message

 Once the 'saal' packet is transformed back into a normal DS1 SSCOP
 PDU, the SSCOP PDU is passed to the SAAL layer for receive
 processing.  If the SSCOP PDU is a peer to peer pdu, it is processed
 completely in the appropriate SAAL layer.  If the SSCOP PDU is an SS7
 MSU, the MSU is transformed back to a normal SS7 MSU and is routed
 within the SG according to the normal SS7 routing procedures.

Sprague, et al. Informational [Page 34] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

3.3 TALI Timers

 Version 1.0 of the TALI specification defined 4 TALI timers that are
 used as part of the TALI state machine.  These timers are generically
 named 'T1' through 'T4'.  Brief descriptions of each timer are
 provided in the following subsections.  Timer expiration events for
 each of the T1-T4 timers appear as inputs to the TALI state machine.
 For exact processing of each timer (when to start/stop, how to
 process timer expirations), refer to the TALI state machine.
 Both ends of the TALI connection have there own T1-T4 timers.  The
 T1-T4 timer values can be set on each end of the connection
 independent of the settings on the far end.  For each timer, a
 default value and range is recommended in the following sections.

3.3.1 T1 Timer

 The T1 timer represents the time interval between the origination of
 a 'test' message at each TALI implementation.  Each time T1 expires,
 the TALI implementation should send a 'test'.

3.3.2 T2 Timer

 The T2 timer represents the amount of time that the Peer has to
 return an 'allo' or a 'proh' in response to a 'test'.  If the far end
 fails to reply with 'allo' or 'proh' before T2 expires, the sender of
 the 'test' treats the T2 expiration as a protocol violation.  Note
 that T2 must be < T1 in order for these timers to work as designed.

3.3.3 T3 Timer

 The T3 timer controls how long the near end should continue to
 process Service Data that is received from the far end after a
 Management Prohibit Traffic Event has occurred (at the near end).
 This timer is used when a transition from NEA-FEA (both ends allowed
 to send service data) to NEP-FEA (only far end willing to send
 service data) occurs.  On that transition, it is reasonable to expect
 that the far end needs some amount of time to adjust its TALI state
 machine and divert service data traffic away from this socket.  The
 T3 timer controls the amount of time the far end has to divert
 traffic.

3.3.4 T4 Timer

 The T4 timer represents the time interval between the origination of
 a 'moni' message at each TALI implementation.  Each time T4 expires,
 the TALI implementation should send a 'moni'.

Sprague, et al. Informational [Page 35] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

3.3.5 Recommended Defaults and Ranges for the TALI Timers

 The following table provides the recommended default and configurable
 range for each TALI timer.
 +------------------------------------------------------------------+
 |Name|  Min  |  Max  |Default| Description                         |
 +------------------------------------------------------------------+
 | T1 | 100ms | 60sec | 4 sec | Send test PDU timer                 |
 +------------------------------------------------------------------+
 | T2 | 100ms | 60sec | 3 sec | Response timer for an allo or proh  |
 |    |       |       |       | response to test message.           |
 +------------------------------------------------------------------+
 | T3 | 100ms | 60sec | 5 sec | Timer controls how long to process  |
 |    |       |       |       | rcvd serv data after an NE          |
 |    |       |       |       | transition from NEA to NEP.  System |
 |    |       |       |       | is waiting for a proa response to   |
 |    |       |       |       | the first proh send when NE         |
 |    |       |       |       | transitions from NEA to NEP.        |
 +------------------------------------------------------------------+
 | T4 | 100ms | 60sec |10 sec | Send moni PDU timer                 |
 +------------------------------------------------------------------+
                       Table 5: Timers
 NOTE: The value of T1 must be at least one (1) millisecond greater
 than T2.  This is to prevent the system from a lockup in the T1
 expired condition.  If T1 is equal or less than T2, it will expire
 and restart T2 and not enforce responses to the test message.
 Enforcement of minimum and maximum timer values is implementation
 dependent.

3.4 TALI User Events

 Each TALI implementation must provide several user event controls
 over the behavior of the TALI state machine for each TALI connection.
 The user interface to provide these capabilities is implementation
 specific.

3.4.1 Management Open Socket Event

 The 'mgmt open socket' event, together with the 'mgmt close socket'
 event, allows the user to control when each defined TALI connection
 will form a TCP socket connection.  When 'open socket' for a
 particular TALI connection occurs, the TALI connection should begin
 trying to form a TCP socket connection to the peer.

Sprague, et al. Informational [Page 36] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

 The steps that are taken to connect are dependent on the
 client/server role of that end of the TALI connection.  The exact
 steps to perform these tasks are implementation dependent and may
 differ based on the TCP stack being used.
 In general, TALI clients form socket connections by using the BSD
 sockets calls:
       Socket()
       Bind()
       Connect()
 In general, TALI servers form socket connections by using the BSD
 sockets calls:
       Socket()
       Bind()
       Listen()
       Accept()

3.4.2 Management Close Socket Event

 The 'mgmt close socket' event can be issued by the user when it is
 desired that the TCP socket for a TALI socket, be closed immediately,
 or discontinue its attempts to connect to the peer.  After acting on
 'close socket', the TALI connection will not be established until
 'mgmt open socket' is issued.

3.4.3 Management Allow Traffic Event

 The 'mgmt allow traffic' event, together with the 'mgmt prohibit
 traffic' event, allows the user to control when each defined TALI
 connection will be willing to carry SS7 service data over that
 particular TALI connection.  When 'mgmt allow traffic' is issued, the
 TALI implementation becomes willing to carry service data.  The TALI
 state for the near end should transition to NEA (near end allowed) if
 the connection is already established.

3.4.4 Management Prohibit Traffic Event

 The 'mgmt prohibit traffic' event is the opposite of 'allow traffic'.
 When 'mgmt prohibit traffic' is issued, the TALI implementation
 becomes un-willing to carry SS7 service data over that particular
 TALI connection.  The TALI state for the near end should transition
 to NEP (near end prohibited) if the connection is already
 established.

Sprague, et al. Informational [Page 37] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

3.5 Other Implementation Dependent TALI Events

 In addition to timers, each TALI implementation needs to be able to
 detect, and react accordingly, for the following events:
  • Connection Established. When the TCP socket connection is

initially established the TALI state machine must be notified.

  • Connection Lost. When the TCP socket connection is lost, due to

socket errors during reads/writes, the TALI state machine must be

    notified.
  • Protocol Violations. Any violation of the TALI protocol as

discussed in 3.7.1.3.

3.6 TALI States

 The TALI version 1.0 specification is based on a state machine that
 considers 6 TALI states.  Each end of the TALI connection maintains
 its own TALI state.

Sprague, et al. Informational [Page 38] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

 +------------------------------------------------------------------+
 | Name       | Description                                         |
 +------------------------------------------------------------------+
 | OOS        | The TALI connection is out of service.  This usually|
 |            | corresponds to a user event to 'close' the socket,  |
 |            | or a user event to 'deactivate the SS7 link'.       |
 +------------------------------------------------------------------+
 | Connecting | The TALI layer is attempting to establish a TCP     |
 |            | socket connection to the peer.  Servers are         |
 |            | 'accepting', clients are 'connecting'.              |
 +------------------------------------------------------------------+
 | NEP-FEP    | The TCP socket connection is established.  Neither  |
 |            | side of the connection is ready to use the socket   |
 |            | for service PDUs.                                   |
 +------------------------------------------------------------------+
 | NEP-FEA    | The TCP socket connection is established.  The NE is|
 |            | not ready to use the socket for service PDUs.  The  |
 |            | FE is ready to use the socket for service PDUs.     |
 +------------------------------------------------------------------+
 | NEA-FEP    | The TCP socket connection is established.  The NE is|
 |            | ready to use the socket for service PDUs.  The FE is|
 |            | not ready to use the socket for service PDUs.       |
 +------------------------------------------------------------------+
 | NEA-FEA    | The TCP socket connection is established.  Both     |
 |            | sides are ready to use the socket for service PDUs. |
 |            | This is the only state where normal bi-directional  |
 |            | SS7 data transfer occurs.                           |
 +------------------------------------------------------------------+
                            Table 6: TALI States

3.7 TALI Version 1.0 State Machine

 This section provides the state machine that must be followed by each
 TALI implementation in order to be compliant with this specification.

3.7.1 State Machine Concepts

 Before presenting the actual state machine, several concepts are
 discussed.

3.7.1.1 General Protocol Rules

 1.  Neither side can send service data unless both sides are allowed.
 2.  Each side initializes to the prohibited state for both near end
     and far end.

Sprague, et al. Informational [Page 39] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

 3.  State changes between the NEx-FEx states are signaled with either
     an 'allo' or 'proh'.
 4.  Each side can poll the far end's state with a 'test'.  Upon
     sending 'test', T1 and T2 should always be restarted.
 5.  Each side polls the far end with a 'test' every T1 expiration.
 6.  The reply to a 'test' is based on the state of the near end only.
 7.  The reply to a 'test' is either 'allo' or 'proh'.
 8.  A far end signals the last service PDU has been transmitted with
     either a 'proh' or a 'proa'.
 9.  Upon receiving a 'proh', the receiver must always reply with
     'proa'.
 10. The NE cannot gracefully close a socket unless a 'proh' is sent
     and 'proa' is received.
 11. On the transition from NEA to NEP, after sending a 'proh', the
     near end must continue to process received service data until a
     'proa' is received or until a T3 timer expires.

3.7.1.2 Graceful Shutdown of a Socket

 The state table treats a management request to close the socket as a
 'hard' shutdown.  That is, it will close the socket immediately
 regardless of the current state.  Therefore, the correct steps to
 ensure a graceful shutdown of a socket (from the NEA_FEP or NEA_FEA
 states) is:
 1. Management issues a Management Prohibit Traffic Event on the
    socket.
 2. Management will wait for T3 to expire.
 3. Management can then issue a Close Socket Event on the socket.

3.7.1.3 TALI Protocol Violations

 Each TALI implementation must detect when violations of the TALI
 protocol have occurred and react accordingly.  Protocol violations
 include:
  • Invalid sync code in a received message

Sprague, et al. Informational [Page 40] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

  • Invalid opcode in a received message
  • Invalid length field in a received message
  • Not receiving an 'allo' or 'proh', in response to the origination

of a 'test' , before the T2 timer expires

  • Receiving Service Messages on a prohibited socket.
  • TCP Socket errors - Connection Lost
 In the state machine that follows, State/Event combinations that
 should be treated as protocol violations are indicated via a 'PV' in
 the state/event cell.  All of the 'PV' events are then processed as
 per the 'Protocol Violation' row in the table.

3.7.2 The State Machine

 Internal Data required for State Machine:
 boolean sock_allowed.  This flag indicates whether the NE is allowed
 to carry Service Messages.
 Initial Conditions:
 sock_allowed = FALSE
 state = OOS
 no timers running
 +------------------------------------------------------------------+
 |   State| OOS  |Connecting| NEP-FEP | NEP-FEA | NEA-FEP | NEA-FEA |
 |Event   |      |          |         |         |         |         |
 +------------------------------------------------------------------+
 |T1 Exp. |      |          |Send test|Send test|Send test|Send test|
 |        |      |          |Start T1 |Start T1 |Start T1 |Start T1 |
 |        |      |          |Start T2 |Start T2 |Start T2 |Start T2 |
 +------------------------------------------------------------------+
 |T2 Exp. |      |          |   PV    |   PV    |   PV    |   PV    |
 +------------------------------------------------------------------+
 |T3 Exp. |      |          |   PV    |   PV    |         |         |
 +------------------------------------------------------------------+
 |T4 Exp. |      |          |Send moni|Send moni|Send moni|Send moni|
 |        |      |          |Start T4 |Start T4 |Start T4 |Start T4 |
 +------------------------------------------------------------------+
 |Rcv test|      |          |Send proh|Send proh|Send allo|Send allo|
 +------------------------------------------------------------------+
 |Rcv allo|      |          | Stop T2 | Stop T2 | Stop T2 | Stop T2 |
 |        |      |          | NEP-FEA |         | NEA-FEA |         |

Sprague, et al. Informational [Page 41] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

 +------------------------------------------------------------------+
 |Rcv proh|      |          | Stop T2 | Stop T2 | Stop T2 | Stop T2 |
 |        |      |          |Send proa|Send proa|Send proa|Flush or |
 |        |      |          |         | NEP-FEP |         | reroute |
 |        |      |          |         |         |         |Send proa|
 |        |      |          |         |         |         | NEA-FEP |
 +------------------------------------------------------------------+
 |Rcv proa|      |          | Stop T3 | Stop T3 |         |         |
 +------------------------------------------------------------------+
 |Rcv moni|      |          |Convert  |Convert  |Convert  |Convert  |
 |        |      |          | to mona | to mona | to mona | to mona |
 |        |      |          |Send mona|Send mona|Send mona|Send mona|
 +------------------------------------------------------------------+
 |Rcv mona|      |          |Implemen-|Implemen-|Implemen-|Implemen-|
 |        |      |          |tation   |tation   |tation   |tation   |
 |        |      |          |dependent|dependent|dependent|dependent|
 +------------------------------------------------------------------+
 |Rcv     |      |          |   PV    |If T3 run|   PV    |Process  |
 | Service|      |          |         | Process |         |         |
 |        |      |          |         |Else PV  |         |         |
 +------------------------------------------------------------------+
 |Connect.|      | Start T1 |         |         |         |         |
 |Estab.  |      | Start T2 |         |         |         |         |
 |        |      | Start T4 |         |         |         |         |
 |        |      |(if non-0)|         |         |         |         |
 |        |      |if sock_  |         |         |         |         |
 |        |      |  allowed |         |         |         |         |
 |        |      |  = TRUE  |         |         |         |         |
 |        |      | send allo|         |         |         |         |
 |        |      | send test|         |         |         |         |
 |        |      | NEA-FEP  |         |         |         |         |
 |        |      |else      |         |         |         |         |
 |        |      | send proh|         |         |         |         |
 |        |      | send test|         |         |         |         |
 |        |      | NEP-FEP  |         |         |         |         |
 +------------------------------------------------------------------+
 |Connect.|      |          |   PV    |   PV    |   PV    |   PV    |
 |Lost    |      |          |         |         |         |         |
 +------------------------------------------------------------------+
 |Protocol|      |          |Stop all |Stop all |Stop all |Stop all |
 |Violat. |      |          | timers  | timers  | timers  | timers  |
 |        |      |          |Close the|Close the|Close the|Close the|
 |        |      |          | socket  | socket  | socket  | socket  |
 |        |      |          |Connect- |Connect- |Connect- |Connect- |
 |        |      |          |  ing    |  ing    |  ing    |  ing    |

Sprague, et al. Informational [Page 42] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

 +------------------------------------------------------------------+
 |Mgmt.   |Open  |          |         |         |         |         |
 |Open    |socket|          |         |         |         |         |
 |Socket  |Conne-|          |         |         |         |         |
 |        | cting|          |         |         |         |         |
 +------------------------------------------------------------------+
 |Mgmt.   |      |Close the |Stop all |Stop all |Stop all |Stop all |
 |Close   |      | socket   | timers  | timers  | timers  | timers  |
 |Socket  |      |OOS       |Close the|Close the|Close the|Close the|
 |        |      |          | socket  | socket  | socket  | socket  |
 |        |      |          |OOS      |OOS      |OOS      |OOS      |
 +------------------------------------------------------------------+
 |Mgmt.   |sock_ |sock_allo-|sock_all-|sock_all-|sock_all-|sock_all-|
 |Prohibit|allow-| wed=FALSE| owed=   | owed=   | owed=   | owed=   |
 |Socket  |ed =  |          | FALSE   | FALSE   | FALSE   | FALSE   |
 |        |FALSE |          |         |         |send proh|send proh|
 |        |      |          |         |         |start t3 |start t3 |
 |        |      |          |         |         | NEP-FEP | NEP-FEA |
 |        |      |          |         |         |         |         |
 +------------------------------------------------------------------+
 |Mgmt.   |sock_ |sock_allo-|sock_all-|sock_all-|sock_all-|sock_all-|
 |Allow   |allow-| wed=TRUE | owed=   | owed=   | owed=   | owed=   |
 |Traffic |ed =  |          | TRUE    | FALSE   | TRUE    | TRUE    |
 |        |TRUE  |          |send allo|send allo|         |         |
 |        |      |          | NEA-FEP | NEA-FEA |         |         |
 +------------------------------------------------------------------+
 |User    |reject| reject   | reject  | reject  | reject  | send    |
 |Part    |data  | data     | data    | data    | data    | data    |
 |Msgs.   |      |          |         |         |         |         |
 +------------------------------------------------------------------+
                   Table 7: TALI 1.0 State Machine

3.8 TALI 1.0 Implementation Notes

 Several aspects of the expected TALI 1.0 implementation have not been
 specifically addressed in the state machine or previous text (or else
 they were presented but will be reiterated here).  These
 implementation notes in some cases have to do with the expected
 behavior of the software layer above the TALI layer.

3.8.1 Failure on a TCP/IP Socket

  • The failure to read or write from a TCP socket shall be detected

and generate a connection lost event.

Sprague, et al. Informational [Page 43] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

3.8.2 Congestion on a TCP/IP Socket

  • Message streams can be monitored for congestion via implementation

dependent methods.

  • One possible definition of congestion for the previous requirement

might be when a TCP socket is blocked.

3.9 TALI 1.0 Limitations

 Several limitations with the TALI 1.0 specification and
 implementation are identified:
  • For SCCP traffic, only UDT and XUDT Class 0 and Class 1 traffic

should be managed by this protocol.

  • When the MTP3 Routing Label is not part of the data transmitted

across the wire, priority zero (0) traffic is used for all traffic

    when the SIO is regenerated.

4. TALI Version 2.0

 Version 2.0 of the TALI specification provides several additions to
 the Version 1.0 specification.  The 2.0 additions are provided by
 introducing three new TALI opcodes.  The basic functionality and most
 of the details of the TALI 1.0 implementation are NOT changed by the
 2.0 additions.

Sprague, et al. Informational [Page 44] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

 The table below provides a summary of the messages and message
 structure used in TALI version 2.0.
 +------------------------------------------------------------------+
 | OCTET | DESCRIPTION           | SIZE     | VALUE  |    TYPE      |
 +------------------------------------------------------------------+
 | 0..3  | SYNC                  | 4 Octets |        | 4 byte ASCII |
 +------------------------------------------------------------------+
 |       |   TALI                |          | 'TALI' |              |
 +------------------------------------------------------------------+
 | 4..7  | OPCODE                | 4 Octets |        | 4 byte ASCII |
 +------------------------------------------------------------------+
 |       |   Test Service        |          | 'test' |              |
 |       |   Allow Service       |          | 'allo' |              |
 |       |   Prohibit Service    |          | 'proh' |              |
 |       |   Prohibit Service Ack|          | 'proa' |              |
 |       |   Monitor Socket      |          | 'moni' |              |
 |       |   Monitor Socket Ack  |          | 'mona' |              |
 |       |   SCCP Service        |          | 'sccp' |              |
 |       |   ISUP Service o/TALI |          | 'isot' |              |
 |       |   MTP3 Service o/TALI |          | 'mtp3' |              |
 |       |   Service o/SAAL      |          | 'saal' |              |
 |       |   Management Message  |          | 'mgmt' |              |
 |       |   Extended Service Msg|          | 'xsrv' |              |
 |       |   Special Message     |          | 'spcl' |              |
 +------------------------------------------------------------------+
 | 8..9  | LENGTH                | 2 Octets |        | integer      |
 |       |   (least significant  |          |        |              |
 |       |    byte first) non-0  |          |        |              |
 |       |    if Service or      |          |        |              |
 |       |    Socket monitor msg |          |        |              |
 +------------------------------------------------------------------+
 | 10..X | DATA PAYLOAD          | variable |        | variable     |
 +------------------------------------------------------------------+
 Due to the minimal amount of change from 1.0, this chapter will only
 provide:
  • Detailed information regarding how a TALI implementation can

identify itself as a 2.0 vs. a 1.0 implementation

  • Detailed information regarding how to provide backward

compatibility for a connection to a far end that is only TALI 1.0

    capable
  • Detailed information regarding the new 2.0 opcodes

Sprague, et al. Informational [Page 45] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

  • Detailed information regarding any other changes to the

information presented in previous sections that need to be

    implemented in order to be 2.0 compatible.
 Therefore, readers of this chapter should read this from the point of
 view of modifying an existing TALI 1.0 implementation to support the
 new 2.0 features.

4.1 Overview of TALI Version 2.0 Features

 A small number of changes to a 1.0 TALI implementation are required
 to support 2.0.  Figure 10 illustrates the inputs that affect the 2.0
 TALI State Machine.  The reader may notice that the only differences
 from the inputs for 1.0 are as follows:
 Three new TALI opcodes can be sent/received between a TALI node and
 its peer.  The new opcodes are:
  • 'mgmt'
  • 'xsrv'
  • 'spcl'
 Three new User Part capabilities need to be supported by the layer of
 code above the TALI layer in each implementation.  The user part
 needs to provide support for 'mgmt', 'xsrv', and 'spcl' data.
 More information about the 3 new opcodes is provided in individual
 sections in this chapter.  However, a brief description of the
 purpose of each of these opcodes is as follows:
  • 'mgmt' - This opcode is intended to allow MANAGEMENT data, or data

that will manage the operation of the device, to pass between the

    TALI endpoints.  Examples of this management data include:
  • configuration data, such as which SS7 traffic streams a peer

would like to receive over a specific socket

  • SS7 Network Management data, such as information regarding

point code (un)availability and congestion.

  • Enabling/disabling various socket options, such as options

regarding which messages are supported, or how to format data.

Sprague, et al. Informational [Page 46] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

  • 'xsrv' - Extended Service Opcodes. It is envisioned that the TALI

protocol could be extended to carry other types of traffic that

    are not covered by the 1.0 service data opcodes ('sccp', 'isot',
    'mtp3', or 'saal').  By defining a new 'xsrv' service opcode, the
    TALI protocol is opened up to the possibility of being used for
    other types of data transport.
  • 'spcl' - Special services. It is envisioned that vendors may want

to build special services into their TALI implementations that are

    only activated when the implementation is connected to other
    equipment implementing the same special services.  This opcode is
    intended to provide a general means to discover more information
    regarding who the TALI session is connected to, and a means to
    enable special features based on the vendor/implementation on the
    far end.

Sprague, et al. Informational [Page 47] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

 +====+    +---------+                    +============+
 |    |    | Service | +-------------+    |            |
 |User|    | Message,| | Mgmt. Open  |    | MANAGEMENT |
 |Part|<-->| MGMT,   | | Mgmt. Close |<-->|            |
 |    |    | XSRV,   | | Mgmt. Proh. |    |            |
 |    |    | SPCL    | | Mgmt. Allow |    +============+
 +====+    +---------+ +-------------+
                 ^            ^
                 |            |
                 v            v
 +========================================================+
 |                 TALI State Machine                     |
 +========================================================+
       ^               ^                 ^             ^
       |               |                 |             |
       v               |                 |             |
  +---------+          |                 |             |
  | Received|   +-----------------+ +-----------+ +------------+
  | 'test', |   | Connection est. | | Protocol  | | T1 Expired |
  | 'allo', |   | Connection lost | | Violation | | T2 Expired |
  | 'proh', |   |                 | |           | | T3 Expired |
  | 'proa', |   +-----------------+ +-----------+ | T4 Expired |
  | 'moni', |          ^                  ^       +------------+
  | 'mona', |          |                  |             ^
  | 'mgmt', |          |                  |             |
  | 'xsrv', |          |                  |             |
  | 'spcl', |          |                  |             |
  |   or    |    +========================================+
  | Service |    |         IMPLEMENTATION                 |
  | Message |    |           DEPENDENT                    |
  +---------+    +========================================+
       ^
       |
       v
   +============+
   |    PEER    |
   |            |
   +============+
   Figure 10: Overview of Inputs to the TALI 2.0 State Machine

4.2 TALI Version Identification

 The TALI 1.0 specification did not provide a simple means to perform
 TALI version identification.  However, the general purpose 'moni'
 message from 1.0 can be used to solve this problem in 2.0.

Sprague, et al. Informational [Page 48] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

 Recall from 1.0 that the 'moni' message was very loosely defined in
 the 1.0 spec:
  • The primary purpose of the 'moni' message was to provide a general

purpose ECHO capability. It was envisioned that an important task

    that the ECHO capability could provide would be to measure Round
    Trip TALI/TALI processing time.
  • The data portion of the 'moni' message could be from 0-200 bytes

long. The use of the data area was completely implementation

    specific.
  • There were no requirements that an implementation ever send a

'moni'.

  • If an implementation did send 'moni', it should use the T4 timer

to control the frequency of the outgoing 'moni'.

  • The receiver of the 'moni' should not make any assumptions as to

the data portion of the 'moni'. The receiver should simply

    convert the 'moni' into a 'mona' and return the message with the
    same data portion.
 TALI 2.0 implementations should use the 'moni' message to provide
 version identification as per the following bullets:
  • The primary purpose of the 'moni' message is now twofold:
  • To provide version identification
  • To continue to provide a general purpose ECHO capability that

can be used to measure Round Trip time or perform other

       implementation specific tasks.
  • The data portion of the 'moni' message is now divided into 2

portions

  • A portion dedicated to version identification, 12 bytes long,

with a specific format that must be followed

  • Followed by a free format section that can be used in a

completely implementation specific manner.

  • The overall length of the data portion for a 'moni' should still

not exceed 200 bytes. This is required to maintain backward

    compatibility with 1.0 implementations that may check for a
    maximum length of 200 bytes on the 'moni' opcode.

Sprague, et al. Informational [Page 49] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

  • If a TALI implementation wants to identify itself as a version 2.0

node, it must send a 'moni' encoded as per Table 8. Every 'moni'

    it sends should conform to the encoding in Table 8.  The version
    label should not change from 'moni' to 'moni'.  The data following
    the version label can change from 'moni' to 'moni' and can
    continue to be used for RTT calculations, or other purposes.
  • If a TALI implementation is trying to determine if the far end of

the TALI connection has implemented version 2.0, the

    implementation must examine any received 'moni' messages that
    arrive from the far end and see if they conform to the new
    stricter 'moni' encoding in Table 8.  On receiving 'moni', a TALI
    2.0 node will compare the 12 bytes of data in the VER LABEL field
    with a list of predetermined strings to determine the
    functionality of the TALI node it is connected to.  If the data
    doesn't match any of the predetermined strings, the Far End is
    assumed to be a TALI 1.0 node.
  • Each TALI implementation must assume that the far end of the

connection is a 1.0 implementation until an arriving 'moni'

    announces that the far end supports TALI version 2.0.  If a 'moni'
    never arrives, the implementation knows the far end has
    implemented version 1.0 of the specification.
  • TALI 1.0 implementations can receive newly encoded 'moni' messages

and simply ignore the data. The 1.0 implementations will continue

    to operate as if the far end is always a 1.0 node (ignore the data
    portion of the 'moni', convert 'moni' to 'mona', and return the
    'mona').
  • The next section provides more information regarding backwards

compatibility (2.0 implementations connected to devices that

    implemented version 1.0 of the specification).

Sprague, et al. Informational [Page 50] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

 +------------------------------------------------------------------+
 | Octets | Field Name  | Description                  | Field Type |
 +------------------------------------------------------------------+
 | 0..3   | SYNC        | 'TALI'                       |4 byte ASCII|
 +------------------------------------------------------------------+
 | 4..7   | OPCODE      | 'moni'                       |4 byte ASCII|
 +------------------------------------------------------------------+
 | 8..9   | LENGTH      | Length (includes the version | Integer    |
 |        |             | label and data fields)       |            |
 +------------------------------------------------------------------+
 | 10..21 | Ver. Label  | 'vers xxx.yyy'               | 12 byte    |
 |        | See note    |                              | ASCII      |
 +------------------------------------------------------------------+
 | 22..X  | DATA        | Vendor Dependent             | Variable   |
 |        |             | Maximum length of this       |            |
 |        |             | message (as coded in octets 8|            |
 |        |             | -9, and stored in bytes 10-X)|            |
 |        |             | should not exceed 200 bytes. |            |
 +------------------------------------------------------------------+
             Table 8: Version Control 'moni' Message
 NOTE: xxx.yyy = provides the Major and Minor release number of the
                 TALI specification being implemented.
       001.000 = Tali version 1.0
       002.000 = Tali version 2.0     // this specification.
       002.001 = Tali version 2.1     // a minor change to 2.0
       003.000 = Tali version 3.0
       and so on.
 The 'vers 002.000' field is an 12 byte field of field type 'ascii
 text'.  As such, 'v' should be the first byte of the field that is
 transmitted out the wire.

4.3 Backwards Compatibility

 As part of adding new functionality to the TALI specification,
 backwards compatibility from TALI version 2.0 to version 1.0 is
 required.  Backwards compatibility is important since TALI 2.0 nodes
 may be connected to far ends that only support version 1.0; it is
 important that these 2 implementations continue to inter-operate, and
 that the 2.0 node falls back to supporting only 1.0 opcodes in this
 situation.
 The previous section described how a TALI 2.0 implementation can use
 the 'moni' it sends to identify itself as a 2.0 node and how it can
 use the 'moni' it receives to determine if the far end is also a 2.0

Sprague, et al. Informational [Page 51] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

 node.  In addition to the discussion in the previous section, the
 following bullets provide details regarding how backwards
 compatibility must be achieved:
  • As documented in the version 1.0 specification, TALI 1.0

implementations that receive TALI messages with 'mgmt', 'xsrv',

    and 'spcl' opcodes will treat the message as a Protocol Violation
    (invalid opcode received).  The Protocol Violation will cause the
    socket to be dropped immediately.
  • It is therefore required that a 2.0 implementation only send

'mgmt', 'xsrv', and 'spcl' opcodes, after it has used a received

    'moni' message to determine that the far end is a 2.0 (or later)
    implementation and has identified itself as a 2.0 (or later)
    implementation.
  • Each TALI 2.0 implementations must use the 'moni' as described in

the previous section to identify themselves as 2.0, and to learn

    if the far end is 2.0.
  • Each TALI 2.0 implementation should maintain a variable as part of

its state machine, 'far_end_version'. The 'far_end_version'

    should be initialized to 1.0 when the socket is established.  Each
    time a 2.0 implementation receives 'moni', it should update the
    'far_end_version' variable.  If the 'moni' did not contain a
    version label, the 'far_end_version' should be reset to 1.0.  If
    the 'moni' did contain a version label for 2.0 (or a later
    version), the 'far_end_version' should be set accordingly.
  • Each time a 2.0 implementation receives a new 2.0 opcode ('mgmt',

'xsrv', and 'spcl') from the far end, it should examine the '

    far_end_version'.  If the 'far_end_version' indicates the far end
    is a 1.0 implementation, the received TALI message should be
    treated as a Protocol Violation (invalid opcode).  If the
    'far_end_version' is 2.0 (or later), the 2.0 implementation should
    process the received 'mgmt/xsrv/spcl' according to that nodes
    capabilities for that opcode.
  • Each time a 2.0 implementation receives a request to send a TALI

message with a 2.0 opcode ('mgmt/xsrv/spcl') from a higher layer

    of software, it should examine the 'far_end_version'.  If the
    'far_end_version' indicates the far end is a 1.0 implementation,
    the request to send the 2.0 opcode should be denied or ignored (an
    implementation decision) and the 2.0 opcode must NOT be sent to
    the far end.  If the 'far_end_version' indicates the far end is
    2.0 (or later), the request can be satisfied and the TALI message
    with the 2.0 opcode can be sent to the far end.

Sprague, et al. Informational [Page 52] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

  • Each TALI 2.0 implementation can provide a varying level of

support for each of the three new 2.0 opcodes ('mgmt/xsrv/spcl').

    In other words, an implementation may wish to only support SOME OF
    the primitives within the new opcodes.  The level of support for
    each 2.0 opcode ('mgmt/xsrv/spcl') is independent of the other two
    2.0 opcodes.
  • The basic message structure for TALI messages using the new 2.0

opcodes is presented in Table 9.

  • The minimal level of support that is required for each of the 2.0

opcodes (mgmt/xsrv/spcl) is to be able to receive TALI messages

    with these opcodes, recognize the new opcode, and ignore the
    message without affecting the state machine.  The TALI state
    should not change.  The socket connection should stay up.  In
    other words, a 2.0 implementation can elect to ignore any received
    'mgmt/xsrv/spcl' messages, if that implementation does not care to
    support the capability intended by that particular opcode.
  • A partial level of support for a 2.0 opcode could be implemented.

Partial support may consist of understanding the data structure

    for the 2.0 opcode, but only supporting some of the variants of
    the opcode.  The message structure for each of the new 2.0 opcodes
    consists of an extra 'Primitive' field that follows the TALI
    opcode and message length fields.  Each 'Primitive' is used to
    differentiate a variant of the opcode.  It is envisioned that each
    new 2.0 opcode can be extended by adding new 'Primitives', as more
    capabilities are defined for the opcode, without having to add new
    TALI opcodes.  A 2.0 implementation may understand and be willing
    to act on some of the 'Primitives' for an opcode, but not others.
    Receiving variants of a 2.0 opcode that an implementation does not
    understand need to be ignored and not affect the 2.0 state
    machine.
  • The full level of support for a 2.0 opcode could be implemented.

This support would consist of understanding and fully supporting

    every 'Primitive' within the 2.0 opcode.

Sprague, et al. Informational [Page 53] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

 +------------------------------------------------------------------+
 | Octets | Field Name  | Description                  | Field Type |
 +------------------------------------------------------------------+
 | 0..3   | SYNC        | 'TALI'                       |4 byte ASCII|
 +------------------------------------------------------------------+
 | 4..7   | OPCODE      | 'mgmt', 'xsrv' or 'spcl'     |4 byte ASCII|
 +------------------------------------------------------------------+
 | 8..9   | LENGTH      | Length (length of the rest   | Integer    |
 |        |             | of this packet)              |            |
 +------------------------------------------------------------------+
 | 10..13 | Primitive   | 'wxyz', or a 4 byte text     |  4 byte    |
 |        | See note    | that is appropriate for the  |  ASCII     |
 |        |             | given opcode                 |            |
 +------------------------------------------------------------------+
 | 14..X  | DATA        | The content of the data area | Variable   |
 |        |             | is dependent on the opcode/  |            |
 |        |             | primitive combination        |            |
 +------------------------------------------------------------------+
     Table 9: Basic Message Structure for New 2.0 TALI Opcodes
 NOTE:  The Primitive field acts as a modifier for each opcode.
 Within an opcode, different operations or groups of operations can be
 defined and supported.  The Primitive identifies each different
 operation or set of operations.

4.3.1 Generating Protocol Violations based on Received Messages

 As implied by some of the bullets before Table 9, it is a goal of the
 2.0 TALI specification to relax some of the error checking associated
 with the processing of received TALI messages.
 Version 1.0 of this specification was very strict in detailing the
 fields that were checked for each received message.  As each received
 message was processed, the SYNC code, opcode and length field of the
 message was checked; if any of these fields were invalid an internal
 protocol violation was generated.  The processing of the protocol
 violation caused the socket to go down.  In addition to the 3
 specific checks (sync, opcode, length), the overall philosophy of
 version 1.0 was to treat any received data that the receiver did not
 understand, or which the receiver deemed to contain incorrectly coded
 fields as protocol violations.
 Version 2.0 introduces the possibility of partial support for
 opcodes, partial support for primitives, and partial support for
 various fields (such as support for ANSI Pt Codes, but not ITU Pt
 Codes).  Thus, the overall philosophy of how to treat received data
 that the receiver does not support needs to be relaxed from the

Sprague, et al. Informational [Page 54] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

 strict treatment in version 1.0.  Version 2.0 implementations should
 be more tolerant when they receive messages they do not support (or
 which they believe contain incorrectly coded fields).  This tolerance
 should include NOT treating these receives as protocol violations.
 Version 2.0 implementations should perform the following level of
 strict/loose checks on the received messages:
  • Checks against the sync codes, opcodes and lengths for version 1.0

and version 2.0 opcodes should be performed (against Table 3 and

    Table 11).  Invalid data in these fields should be treated as
    cause for protocol violations.
  • Checks against the opcode field for messages with new 2.0 opcodes

(mgmt/xsrv/spcl) should be performed to determine whether the

    message can be processed by the implementation.  If an
    implementation chooses to NOT support a particular 2.0 opcode, the
    received message should be discarded, internal data (such as
    measurements, logs of messages, user notifications) could record
    the event, and the TALI state should NOT be affected.
  • Checks against the primitive field for messages with new 2.0

opcodes (mgmt/xsrv/spcl) should be performed to determine whether

    the message can be processed by the implementation.  If an
    implementation does not understand a particular primitive, or has
    chosen NOT to implement the features for a particular primitive,
    the received message should be discarded, internal data (such as
    measurements, logs of messages, user notifications) could record
    the event, and the TALI state should NOT be affected.
  • Checks against other field types in messages with new 2.0 opcodes

(such as checking the encoding of a Point Code field for a valid

    Pt Code type) should also be performed in a 'soft' manner.  Errors
    found in individual fields should cause the received message to be
    discarded, internal data (such as measurements, logs of messages,
    user notifications) could record the event, and the TALI state
    should NOT be affected.
 The goals behind introducing this gentler treatment of errors in
 received data are as follows:
  • To keep the socket up in order to perform the primary purpose of

the connection (ie: to continue to transport SS7 data) in spite of

    improperly formatted/unsupported TALI messages related to other
    features/extensions/etc.

Sprague, et al. Informational [Page 55] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

  • To allow applications to support and use some of the features for

a particular TALI revision without requiring the application to

    implement all of the functionality for the TALI revision.
  • To increase the extensibility of the protocol. Looser receive

checks are preferred in order to be able to add new primitives and

    new primitive operations as they are defined.

4.4 Overview of the TALI Message Structure

 The basic message structure for all TALI messages is unchanged with
 the addition of new 2.0 opcodes.  The base TALI header still consists
 of SYNC + OPCODE + LENGTH, as described in Table 2.
 The message structure for the new 2.0 opcodes was shown in Table 9.
 These messages define an extra required field, PRIMITIVE, that
 follows the LENGTH field of Table 2.

4.4.1 Types of TALI Fields

 Table 4 in the version 1.0 specification provided implementation
 notes for all the 'types of fields' found in the 1.0 specification.
 Version 2.0 of TALI continues to use all of the types provided in
 Table 4, and also defines some new fields that are used in TALI
 messages that use the new 2.0 opcodes.  The following table
 introduces the new field types that are introduced with version 2.0.
 The types in Table 10 are used in addition to the types in Table 4 to
 implement the 2.0 TALI protocol.

Sprague, et al. Informational [Page 56] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

 +-----------+------------------------------------------------------+
 |Field Type | Implementation Notes for that Type                   |
 +------------------------------------------------------------------+
 |SS7 Point  | Used to transmit point code information for ANSI or  |
 |Code       | ITU variants of point codes across the TALI interface|
 |           | * The point code structure is 4 bytes. Byte 3 is used|
 |           |   to identify the TYPE of point code. The actual     |
 |           |   point code is then encoded in bytes 0-2 (w/byte 0  |
 |           |   being the least significant byte and the first byte|
 |           |   transmitted across the wire)                       |
 |           | * Byte 3: encoding of the type of point code (PC)    |
 |           |   0 = an ANSI Full PC                                |
 |           |   1 = an ITU International Full PC w/ a 3/8/3 coding |
 |           |       scheme for zone/area/identifier                |
 |           |   2 = an ITU National Full PC w/ a raw 14 bit PC     |
 |           |   3 = unused                                         |
 |           |   4 = an ANSI Cluster PC                             |
 |           | * For ANSI Full PC w/byte 3=0.  These point codes are|
 |           |   24 bit point codes as follows:                     |
 |           |   Byte 2 = Network                                   |
 |           |   Byte 1 = Cluster                                   |
 |           |   Byte 0 = Member                                    |
 |           | * For ITU International Full PC (3/8/3) w/byte 3=1.  |
 |           |   These point codes use 14 bits (stored in the 14    |
 |           |   least significant bits in bytes 0&1).  Byte 2 is   |
 |           |   unused.  The 14 bits should be interpreted as 3    |
 |           |   bits of zone, 8 bits of area and 3 bits of         |
 |           |   signaling point identifier.  The 3 bits of         |
 |           |   signaling point identifier are the 3 least         |
 |           |   significant bits.                                  |
 |           | * For ITU National Full PC w/byte 3=2. These point   |
 |           |   codes use 14 bits (stored in the 14 least          |
 |           |   significant bits in bytes 0&1).  Byte 2 is unused. |
 |           |   The 14 bits represent a single 14-bit quantity that|
 |           |   constitutes the point code.                        |
 |           | * For unused w/byte 3=3.  Bytes 0 through 2 are      |
 |           |   undefined.                                         |
 |           | * For ANSI Cluster PC, w/byte 3=4.  These point codes|
 |           |   are 24 bit point codes as follows:                 |
 |           |   Byte 2 = Network                                   |
 |           |   Byte 1 = Cluster                                   |
 |           |   Byte 0 = 0. This field is ignored and should be    |
 |           |   coded as 0...all members of the cluster are implied|
 |           | * Byte 0 is the first byte that is transmitted across|
 |           |   the wire, followed by byte 1, byte 2, then byte 3. |

Sprague, et al. Informational [Page 57] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

 +------------------------------------------------------------------+
 |Bit-Field  | * Field containing an array of N bits, where N is a  |
 |           |   multiple of 8.  Bit-Field types should be          |
 |           |   transmitted such that the byte containing bits 0   |
 |           |   through 7 is transmitted across the wire first,    |
 |           |   followed by the byte containing bits 8 through 15, |
 |           |   etc.                                               |
 |           | * The software for each implementation should be     |
 |           |   written in a manner that accounts for the required |
 |           |   byte order of transmission (ie: the Big Endian/    |
 |           |   Little Endian characteristics of the processor need|
 |           |   to be dealt with in the software).                 |
 +------------------------------------------------------------------+
 |Version    |A TALI version label is a 12 byte ASCII text field.   |
 |Label      |The label is of a format 'vers xxx.yyy', where xxx.yyy|
 |           |are used to identify the version such as 002.000.  As |
 |           |with other ASCII text fields, the first byte of the   |
 |           |text field (the 'v') should be the first byte         |
 |           |transmitted out the wire.                             |
 +------------------------------------------------------------------+
 |Primitive  |Messages that use the new TALI 2.0 opcodes all have a |
 |           |4 byte text ASCII field referred to as a Primitive.   |
 |           |The Primitive acts as a modifier for the opcode. This |
 |           |allows a single opcode to be used to perform multiple |
 |           |actions.                                              |
 +------------------------------------------------------------------+
 |Primitive  |A Primitive can be used to specify either a specific  |
 |Operation  |action or a set of actions.  When the Primitive field |
 |           |is used to specify a set of actions, an operation     |
 |           |field is used to pick a specific operation within that|
 |           |group of actions. Operation fields are 4 byte integers|
 +------------------------------------------------------------------+
 |Private    |Various RFC documents have detailed a set of assigned |
 |Enterprise |numbers (RFC 1700, Assigned Numbers) and defined data |
 |Code       |structures (RFC 1155, Structure and Identification of |
 |(PEC)      |Management Information for IP-based Internets)        |
 |           |that are used on IP networks to provide network       |
 |           |management information.                               |
 |           |Network Management Object Identifiers (OID) are used  |
 |           |to recognize specific organizations, companies,       |
 |           |protocols, and so on, in a manner that all vendors can|
 |           |agree on.                                             |
 |           |An Object Identifier exists which uniquely describes  |
 |           |each company that does business in the data/telecomm  |
 |           |industry.  That OID is referred to as an 'SMI Network |
 |           |Management Private Enterprise Code', which we are     |
 |           |shortening to Private Enterprise Code of PEC in this  |
 |           |document for simplicity.  Each PEC is assumed to have |

Sprague, et al. Informational [Page 58] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

 |           |a defined prefix of                                   |
 |           |'iso.org.dod.internet.private.enterprise' or          |
 |           |(1.3.6.1.4.1).                                        |
 |           |                                                      |
 |           |The PEC for each company can be found via a file at:  |
 |           |ftp://ftp.isi.edu/in-notes/iana/assignments/          |
 |           | enterprise-numbers                                   |
 |           |                                                      |
 |           |To encode the PEC for a vendor in each implementation |
 |           |of TALI, a 2 byte integer field is used.  The contents|
 |           |of the integer field should match the PEC code for    |
 |           |that company in the file mentioned above.             |
 |           |                                                      |
 |           |For example, Tekelec, which has a PEC of 323, will    |
 |           |code this 2 byte field as '0x0143'.                   |
 |           |                                                      |
 |           |Like other integer fields, the PEC value is           |
 |           |transmitted Least Significant Byte first across the   |
 |           |ethernet wire.                                        |
 +------------------------------------------------------------------+
 Table 10: Implementation for new field types introduced in TALI 2.0

4.5 Detailed TALI Message Structures for New 2.0 Opcodes

 The message structures for opcodes defined in version 1.0 of TALI are
 unchanged from the information presented earlier, with the exception
 of the 'moni' message.  The 2.0 format for the 'moni' message was
 described earlier.
 Detailed message structures, and discussion of the capabilities, for
 each of the new 2.0 opcodes is provided in the following sections.
 Before discussing each opcode individually, Table 11 provides the
 minimum and maximum value of the LENGTH field that should be
 supported for each new opcode (as well as 'moni/mona').  Table 11
 additionally shows the impact of ITU support that was added in 2.0.
 The routing label for ITU point codes only uses 4 octets instead of 7
 octets as ANSI requires.

Sprague, et al. Informational [Page 59] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

 +------------------------------------------------------------------+
 | Opcode | Valid Length | Comments                                 |
 |        | Field Values |                                          |
 +------------------------------------------------------------------+
 | moni   | 0-200 bytes  | The overall length of the data portion   |
 |        |              | for 'moni' on TALI 2.0 implementations   |
 |        |              | is unchanged from version 1.0 of the     |
 |        |              | specification and remains at 200 bytes   |
 |        |              | to provide backwards compatibility.      |
 +------------------------------------------------------------------+
 | mona   | 0-200 bytes  | The overall length of the data portion   |
 |        |              | for 'mona' on TALI 2.0 implementations   |
 |        |              | is unchanged from version 1.0 of the     |
 |        |              | specification and remains at 200 bytes   |
 |        |              | to provide backwards compatibility.      |
 +------------------------------------------------------------------+
 | mgmt   | 4-4096 bytes | The minimum length of 4 bytes is required|
 |        |              | to provide space for the Primitive field.|
 |        |              | The maximum length allows large TCP      |
 |        |              | packets to be supported if desired.      |
 +------------------------------------------------------------------+
 | xsrv   | 4-4096 bytes | The minimum length of 4 bytes is required|
 |        |              | to provide space for the Primitive field.|
 |        |              | The maximum length allows large TCP      |
 |        |              | packets to be supported if desired.      |
 +------------------------------------------------------------------+
 | spcl   | 4-4096 bytes | The minimum length of 4 bytes is required|
 |        |              | to provide space for the Primitive field.|
 |        |              | The maximum length allows large TCP      |
 |        |              | packets to be supported if desired.      |
 +------------------------------------------------------------------+
 | sccp   | 9-265 bytes  | These are the valid sizes for the        |
 |        |              | SCCP-ONLY portions of SCCP UDT MSUs.     |
 +------------------------------------------------------------------+
 | isot   | 8-273 bytes  | The length is the number of octets that  |
 |        |              | in the MTP3 and higher layer(s) of the   |
 |        |              | SS7 MSU.  This length includes the SIO   |
 |        |              | byte and all bytes in the SIF (Service   |
 |        |              | Information Field) field.  The MTP3      |
 |        |              | routing label is part of the SIF field.  |
 +------------------------------------------------------------------+
 | mtp3   | 8-280 bytes  | The length is the number of octets that  |
 |        |              | in the MTP3 and higher layer(s) of the   |
 |        |              | SS7 MSU.  This length includes the SIO   |
 |        |              | byte and all bytes in the SIF (Service   |
 |        |              | Information Field) field.  The MTP3      |
 |        |              | routing label is part of the SIF field.  |
 +------------------------------------------------------------------+

Sprague, et al. Informational [Page 60] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

 | saal   | 8-280 bytes  | The length is the number of octets that  |
 |        |              | in the MTP3 and higher layer(s) of the   |
 |        |              | SS7 MSU.  This length includes the SIO   |
 |        |              | byte and all bytes in the SIF (Service   |
 |        |              | Information Field) field.  The MTP3      |
 |        |              | routing label is part of the SIF field.  |
 |        |              | Seven (7) octets of SSCOP trailer is     |
 |        |              | added to the message.  The SSCOP trailer |
 |        |              | bytes are also included in the length.   |
 +------------------------------------------------------------------+
   Table 11: Valid Length Fields for Opcodes Affected by TALI 2.0

4.5.1 Management Message (mgmt)

 The 'mgmt' opcode is intended to allow Management data, or data that
 will manage the operation of the device, to pass between the TALI
 endpoints over the socket connection.  'mgmt' messages can be
 received and processed in any of the TALI NEx-FEx states.  Three
 PRIMITIVES are defined for use with this opcode:
  • 'rkrp' - Routing Key Registration Primitive. This primitive

allows the nodes to configure the SS7 traffic streams that they

    wish to receive over each socket.  This 'routing key registration'
    is performed in-band, via TALI messages.
  • 'mtpp' - MTP3 Primitives. This primitive allows SS7 MTP3 network

management messages regarding the (un)availability and congestion

    states of SS7 devices to be passed to the IP devices SG.
  • 'sorp' - Socket Options Registration Primitive. This primitive

allows various socket options to be enabled/disabled by each TALI

    device.
 As of version 2.0, the only defined primitives for the 'mgmt' opcode
 are 'rkrp', 'mtpp', and 'sorp'.  In the future, more primitives can
 be added to this opcode to extend the Management capabilities of the
 SG or IP devices.  The basic message structure for the 2.0 'mgmt'
 messages for all 3 of these primitives is as follows:

Sprague, et al. Informational [Page 61] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

 +------------------------------------------------------------------+
 | Octets | Field Name  | Description                               |
 +------------------------------------------------------------------+
 | 0..3   | SYNC        | 'TALI'                                    |
 +------------------------------------------------------------------+
 | 4..7   | OPCODE      | 'mgmt'                                    |
 +------------------------------------------------------------------+
 | 8..9   | LENGTH      | Length                                    |
 +------------------------------------------------------------------+
 | 10..13 | Primitive   | 'rkrp', 'mtpp' or 'sorp'  Each of these   |
 |        |             | primitives specify a group of applicable  |
 |        |             | management operations.                    |
 +------------------------------------------------------------------+
 | 14..17 | Primitive   | The operation field specifies the one     |
 |        | Operation   | operation within the group of operations  |
 |        |             | identified by the primitive.              |
 +------------------------------------------------------------------+
 | 18..   | Message     | The content of the message data area is   |
 |        | Data        | dependent on the combination of opcode/   |
 |        |             | primitive/operation fields.  Each of those|
 |        |             | combinations could use a different message|
 |        |             | data structure.                           |
 +------------------------------------------------------------------+
            Table 12: Message Structure for 'mgmt' opcode

4.5.1.1 Routing Key Registration Primitive (rkrp)

 The 'rkrp' primitive allows IP nodes to modify the application
 routing key table in the SG by sending TALI messages to configure the
 SS7 traffic streams that they wish to receive over each socket.  This
 'routing key registration' is performed in-band, via TALI messages,
 as an alternative to using the SG user interface to configure the
 routing keys.
 Recall from earlier discussion in this document that the
 specification supports five (5) types of fully specified routing
 keys:
  • A key for SCCP traffic, where key = DPC-SI-SSN, where SI=3.
  • A key for ISUP traffic, where key = DPC-SI-OPC-CIC Range, where

SI=5. The CIC values for traditional ISUP are 14 bit quantities

    in ANSI networks and 12 bit quantities in ITU networks.
  • A key for TUP traffic, where key = DPC-SI-OPC-CIC Range, where

SI=4. This key is only supported for ITU networks. The CIC

    values for TUP keys are 12 bit quantities in ITU networks.

Sprague, et al. Informational [Page 62] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

  • A key for QBICC traffic (an extension of ISUP which uses 32 bit

CIC codes), where key = DPC-SI-OPC-CIC, where SI=13. The CIC

    values for QBICC keys are 32 bit quantities for ANSI and ITU
    networks.
  • A key for OTHER-MTP3-SI (non-SCCP, non-ISUP, non-QBICC for ANSI

and non-SCCP, non-ISUP, non-QBICC, non-TUP for ITU) traffic, where

    key = DPC-SI
 Each of these keys is fully specified key where the exact content of
 the MSU to be routed must match the data in the routing key.
 Extensions to the routing keys have been added that will support
 'partial match' or 'default' routing keys.  The purpose of these
 extensions is to improve the handling of MSU traffic when no fully
 specified routing key exists that matches the MSU.  Partial match and
 default routing keys are used when the SG can not find a fully
 specified routing key that can be used to route an MSU.  Partial
 match keys can be used to provide closest-match routing such as
 'ignore the CIC' for ISUP/QBICC/TUP traffic, or 'ignore the SSN' for
 SCCP traffic.  Default keys are used when no full or partial routing
 key has been  found as a last resort destination to route the MSU to.
 The types of partial and default keys defined by the protocol are
 discussed in the following table.  The 4th column in the table
 indicates the data structure that is used in the TALI rkrp message to
 perform operations on each partial/default key type.  Note: The order
 of the keys in the table (from top to bottom) matches the
 hierarchical search order that an SG will use to attempt to find a
 routing key to use for an MSU.  The partial and default keys are only
 used after attempting to find a fully specified key that matches the
 MSU.

Sprague, et al. Informational [Page 63] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

 +--------+------------+--------------------------------+-----------+
 |Key     | Key        | Comments                       | Cross     |
 |Type    | Attributes |                                | Reference |
 +--------+------------+--------------------------------+-----------+
 |Partial | DPC-SI-OPC |Used as backup routes for CIC   | 4.5.1.1.2 |
 |        |            |based traffic (but ignoring the |           |
 |        |            |CIC field).                     |           |
 +--------+------------+--------------------------------+-----------+
 |Partial | DPC-SI     |Used as backup routes for CIC   | 4.5.1.1.4 |
 |        |            |based or SCCP traffic (but      |           |
 |        |            |ignoring the OPC-CIC or SSN).   |           |
 |        |            |Routes traffic based solely on  |           |
 |        |            |DPC and SI of the MSU.          |           |
 +--------+------------+--------------------------------+-----------+
 |Partial | DPC        |Used as a backup route for any  | 4.5.1.1.4 |
 |        |            |MSU type.  Routes traffic based |           |
 |        |            |solely on the DPC field.        |           |
 +--------+------------+--------------------------------+-----------+
 |Partial | SI         |Used as a backup route for any  | 4.5.1.1.4 |
 |        |            |MSU type.  Routes traffic based |           |
 |        |            |solely on the SI field.         |           |
 +--------+------------+--------------------------------+-----------+
 |Default | -          |If no other type of routing key | 4.5.1.1.5 |
 |        |            |for an MSU can be found, use    |           |
 |        |            |this one.                       |           |
 +--------+------------+--------------------------------+-----------+
  Table 13: Partial and Default Routing Keys (in hierarchical order)
 The specific capability requested in each 'rkrp' message is indicated
 via an 'RKRP Operation' field.  These capabilities include:
  • ENTER: The ENTER operation creates an association between a

specific socket and a specific application routing key. The

    socket of the association is always the socket that the 'rkrp' was
    received on.  The application routing key identifies an SS7
    traffic stream that should be carried over that socket.  Multiple
    sockets can be associated with the same application routing key,
    if so, they all receive traffic in a 'load sharing' mode.  An
    override field can be used to remove any other socket associations
    for a particular routing key and add a single socket association.
    The ENTER operation is applicable for fully specified SCCP keys,
    CIC based keys (ISUP, Q.BICC, and TUP), OTHER-MTP3-SI keys, and
    all types of partial keys and to the default routing key.
  • DELETE: The DELETE operation deletes an association between a

specific socket and a specific application routing key. The

    socket of the association is always the socket that the 'rkrp' was

Sprague, et al. Informational [Page 64] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

    received on.  Other socket associations for the same application
    routing key are NOT affected by the deletion.  When the last
    socket association for a routing key is deleted, the entire
    routing key entry is removed from the database.  The DELETE
    operation operation is applicable for fully specified SCCP keys,
    CIC based keys (ISUP, Q.BICC, and  TUP), OTHER-MTP3-SI keys, and
    all types of partial keys and to the default routing key.
  • SPLIT: The SPLIT operation is used to convert a single application

routing key into 2 application routing keys that together cover

    the same SS7 traffic stream as the original key.  Immediately
    after a split is performed, both of the resulting entries retain
    the same socket associations as the original routing key.  When
    the split is completed, the socket associations can be modified
    for each of the 2 resulting ranges independent of the other range.
    The split operation is only applicable to fully specified CIC
    based keys (ISUP, QBICC, and TUP).  Each fully specified CIC based
    key is uniquely identified by the combination of DPC/SI/OPC/CIC
    range.  The CIC range is a continuous set of numbers from
    CICS(start) to CICE(end); the CIC range in the application routing
    key corresponds to the CIC value in a CIC based MSU.
  • RESIZE: The RESIZE operation is used to modify the CIC range in

for a single application routing key. The resize operation is

    only applicable to fully specified CIC based routing keys.  The
    resize operation replaces the CICS/CICE values for a routing key
    with a new CIC range (NCICS/NCICE).  A wide variety of NCICS/NCICE
    ranges can be supported based on the existing CICS/CICE; just
    about the only restriction is that the new range can not already
    exist in the database and can not overlap any other entry in the
    database.  The socket associations for the routing key are NOT
    affected by the change in CICS/CICE.  The SPLIT operation is
    applicable only to fully specified CIC based keys (ISUP, Q.BICC,
    and TUP).
 The list of RKRP Operations (and their encodings) that are supported
 for TALI version 2.0 is as follows:
             0x0001 - ENTER ISUP KEY
             0x0002 - DELETE ISUP KEY
             0x0003 - SPLIT ISUP KEY
             0x0004 - RESIZE ISUP KEY
             0x0005 - ENTER Q.BICC ISUP KEY
             0x0006 - DELETE Q.BICC ISUP KEY
             0x0007 - SPLIT Q.BICC ISUP KEY
             0x0008 - RESIZE Q.BICC ISUP KEY
             0x0009 - ENTER SCCP KEY
             0x000A - DELETE SCCP KEY

Sprague, et al. Informational [Page 65] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

             0x000B - ENTER OTHER-MTP3-SI KEY
             0x000C - DELETE OTHER-MTP3-SI KEY
             0x000D - ENTER TUP KEY (ITU only)
             0x000E - DELETE TUP KEY (ITU only)
             0x000F - SPLIT TUP KEY (ITU only)
             0x0010 - RESIZE TUP KEY (ITU only)
             0x0011 - ENTER DPC-SI-OPC PARTIAL KEY
             0x0012 - DELETE DPC-SI-OPC PARTIAL KEY
             0x0013 - ENTER DPC-SI PARTIAL KEY
             0x0014 - DELETE DPC-SI PARTIAL KEY
             0x0015 - ENTER DPC PARTIAL KEY
             0x0016 - DELETE DPC PARTIAL KEY
             0x0017 - ENTER SI PARTIAL KEY
             0x0018 - DELETE SI PARTIAL KEY
             0x0019 - ENTER DEFAULT
             0x001A - DELETE DEFAULT KEY
             0x001B - MULTIPLE REGISTRATION SUPPORT
 The message data area of the 'rkrp' messages will differ based on
 which RKRP Operation is specified.  Several different structures are
 used, the correct structure can be identified by the RKRP Operation
 field.
 In order to simplify the implementation, each of these structures
 will define a structure that will support all of the operations
 required for the key type.  This means that based on the rkrp
 operation, some of the fields will be required, and some of the
 fields will not be applicable for each RKRP message.  Unused fields
 should be initialized to 0 by the sender and ignored by the receiver.

4.5.1.1.1 RKRP Data Structures

4.5.1.1.1.1 Common Fields in all RKRP Messages

 In the following subsections several different data structures to be
 used for various RKRP operations are presented.  It should be noted
 that each of these data structures has the following fields in
 common.  The data structure below should begin at byte 14 of the TALI
 message as shown in Table 12.

Sprague, et al. Informational [Page 66] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

 +------------------------------------------------------------------+
 | Octets | Field Name  | Description                  | Field Type |
 +------------------------------------------------------------------+
 | 2      | RKRP        | Identifies which 'rkrp'      | Integer    |
 |        | Operation   | operation is desired.        |            |
 +------------------------------------------------------------------+
 | 2      | Request/    | Identifies whether the 'rkrp'| Integer    |
 |        | Reply       | message is a request (from an|            |
 |        |             | IP node to SG) for some type |            |
 |        |             | of 'rkrp' action, or a reply |            |
 |        |             | to a previous request (from  |            |
 |        |             | the SG back to the IP node). |            |
 |        |             | This integer field uses the  |            |
 |        |             | following encodings:         |            |
 |        |             | 0x0000=Request               |            |
 |        |             | 0x0001=Reply.  See Success/  |            |
 |        |             | Failure code for more info.  |            |
 +------------------------------------------------------------------+
 | 2      | Success/    | Provides a success/failure   | Integer    |
 |        | Failure     | indication as part of the    |            |
 |        | Code        | reply back to the IP node    |            |
 |        |             | for each processed request.  |            |
 |        |             | This field is only used when |            |
 |        |             | the Request/Reply field is   |            |
 |        |             | 0x0001.  This field uses the |            |
 |        |             | encodings from in section 5. |            |
 +------------------------------------------------------------------+
        Table 14: Common Fields in ALL 'rkrp' Data Structures
 The primary purpose of requiring the data structures for all RKRP
 operations to begin with these same fields, is to provide a means for
 a receiver to reply to unknown RKRP messages in a consistent manner.
 When an implementation receives an RKRP request message it does not
 understand, it should turn the request into a reply and use the
 success/failure code to indicate that the operation is not supported
 (with an RKRP Reply Code of Unsupported rkrp Operation).
 It is a requirement that these common fields continue to be used as
 new RKRP operations are added to this specification.  This will
 ensure that the capability described in the previous paragraph will
 always exist.

Sprague, et al. Informational [Page 67] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

4.5.1.1.1.2 CIC Based Routing Key Operations

 The data structure used for 'rkrp' messages related to MSUs which are
 CIC based (ISUP, Q.BICC ISUP, and TUP (ITU only)) is as presented in
 the next table.  The data structure below should begin at byte 14 of
 the TALI message as shown in Table 12.
 Note 1: The number of bits used in each CIC field will vary based on
 the SI and network type.
  • ISUP operations (0x0001 - 0x0004) are assumed to use 14 bit CIC

values from the corresponding fields in the structure when DPC/OPC

    indicate an ANSI network (12 bits used in ITU networks).  Only the
    14(12) least significant bits of the 32 bit CIC field will be
    used.
  • Q.BICC ISUP operations (0x0005 - 0x0008) are assumed to use 32 bit

CIC values from the corresponding fields in the structure.

  • TUP operations (0x000d - 0x0010) are assumed to use 12 bit CIC

values from the corresponding fields in the structure when DPC/OPC

    indicate an ITU network.  Only the 12 least significant bits of
    the 32 bit CIC field will be used.   TUP operations are not
    supported for ANSI networks.
 Note 2: This same structure should be used to specify the partial key
 = DPC-SI-OPC(ignoreCIC).  When specifying a DPC-SI-OPC partial key,
 the CIC fields in this structure should be set to 0 by the sender.
 +------------------------------------------------------------------+
 | Octets | Field Name  | Description                  | Field Type |
 +------------------------------------------------------------------+
 | 2      | RKRP        | Identifies which 'rkrp'      | Integer    |
 |        | Operation   | operation is desired.        |            |
 +------------------------------------------------------------------+
 | 2      | Request/    | Identifies whether the 'rkrp'| Integer    |
 |        | Reply       | message is a request (from an|            |
 |        |             | IP node to SG) for some type |            |
 |        |             | of 'rkrp' action, or a reply |            |
 |        |             | to a previous request (from  |            |
 |        |             | the SG back to the IP node). |            |
 |        |             | This integer field uses the  |            |
 |        |             | following encodings:         |            |
 |        |             | 0x0000=Request               |            |
 |        |             | 0x0001=Reply.  See Success/  |            |
 |        |             | Failure code for more info.  |            |

Sprague, et al. Informational [Page 68] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

 +------------------------------------------------------------------+
 | 2      | Success/    | Provides a success/failure   | Integer    |
 |        | Failure     | indication as part of the    |            |
 |        | Code        | reply back to the IP node    |            |
 |        |             | for each processed request.  |            |
 |        |             | This field is only used when |            |
 |        |             | the Request/Reply field is   |            |
 |        |             | 0x0001.  This field uses the |            |
 |        |             | encodings listed in section  |            |
 |        |             | 5.                           |            |
 +------------------------------------------------------------------+
 | 2      | RKRP flags  | This is a 2 byte bit-field   | Bit-field  |
 |        |             | that provides 16 possible    |            |
 |        |             | flags that can control       |            |
 |        |             | various aspects of the       |            |
 |        |             | operation.                   |            |
 |        |             | Bit 0 - An Override bit is   |            |
 |        |             | used on the ENTER operation  |            |
 |        |             | to control how the socket    |            |
 |        |             | associations for a routing   |            |
 |        |             | key should be manipulated.   |            |
 |        |             | This flag determines if the  |            |
 |        |             | ENTER is to add the given    |            |
 |        |             | socket association in a      |            |
 |        |             | 'load-sharing' mode or if    |            |
 |        |             | the new association should   |            |
 |        |             | replace (Override) all       |            |
 |        |             | existing associations.  This |            |
 |        |             | flag is only examined on     |            |
 |        |             | ENTER operations.            |            |
 |        |             | Bit 0=0, Load Sharing Mode   |            |
 |        |             | Bit 0=1, Override Mode       |            |
 |        |             | Bits 1-15, currently         |            |
 |        |             | undefined                    |            |
 +------------------------------------------------------------------+
 | 1      | SI          | Service Indicator.  The SI   | Integer    |
 |        |             | field in an SS7 MSU          |            |
 |        |             | identifies the type of       |            |
 |        |             | traffic being carried by the |            |
 |        |             | MSU (0=SNM, 3=SCCP, 5=ISUP,  |            |
 |        |             | etc).  Each application      |            |
 |        |             | routing key must specify a   |            |
 |        |             | specific SI value that it    |            |
 |        |             | relates to.                  |            |
 |        |             | SI should be 5 for ISUP keys.|            |
 |        |             | SI should be 13 for Q.BICC   |            |
 |        |             | ISUP keys.                   |            |
 |        |             | SI should be 4 for TUP keys. |            |

Sprague, et al. Informational [Page 69] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

 +------------------------------------------------------------------+
 | 4      | DPC         | Destination Point Code.  Each| SS7 Point  |
 |        |             | SS7 MSU contains a DPC that  | Code       |
 |        |             | identifies the destination   |            |
 |        |             | for the MSU.  Each           |            |
 |        |             | application routing key must |            |
 |        |             | specify a specific DPC value |            |
 |        |             | that it relates to.          |            |
 +------------------------------------------------------------------+
 | 4      | OPC         | Origination Point Code.  Each| SS7 Point  |
 |        |             | SS7 MSU contains a OPC that  | Code       |
 |        |             | identifies the source of the |            |
 |        |             | MSU.  ISUP routing keys must |            |
 |        |             | each specify a single OPC    |            |
 |        |             | that the application routing |            |
 |        |             | key relates to.              |            |
 +------------------------------------------------------------------+
 | 4      | CICS        | Circuit Identification Code  | Integer    |
 |        |             | Start.  Each SS7 ISUP MSU    |            |
 |        |             | contains a CIC code.  Each   |            |
 |        |             | ISUP/QBICC/TUP routing key   |            |
 |        |             | identifies a range of CIC    |            |
 |        |             | values that are applicable   |            |
 |        |             | for the routing key.  The    |            |
 |        |             | CICS value is the low end of |            |
 |        |             | the CIC range.               |            |
 +------------------------------------------------------------------+
 | 4      | CICE        | Circuit Identification Code  | Integer    |
 |        |             | End.  Each SS7 ISUP MSU      |            |
 |        |             | contains a CIC code.  Each   |            |
 |        |             | ISUP/QBICC/TUP routing key   |            |
 |        |             | identifies a range of CIC    |            |
 |        |             | values that are applicable   |            |
 |        |             | for the routing key.  The    |            |
 |        |             | CICE value is the high end   |            |
 |        |             | of the CIC range.            |            |
 +------------------------------------------------------------------+
 | 4      | SPLIT CIC   | The SPLIT field is used on   | Integer    |
 |        |             | the SPLIT operation to       |            |
 |        |             | specify where in the existing|            |
 |        |             | CIC range (given by CICS/    |            |
 |        |             | CICE) an existing routing key|            |
 |        |             | should be split into 2       |            |
 |        |             | routing keys.  To be valid,  |            |
 |        |             | the following relationship   |            |
 |        |             | must be true before the SPLIT|            |
 |        |             | is performed:                |            |
 |        |             |    CICS < SPLIT <= CICE.     |            |

Sprague, et al. Informational [Page 70] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

 |        |             | After the SPLIT is performed,|            |
 |        |             | the 2 routing keys are as    |            |
 |        |             | follows:                     |            |
 |        |             |    CICS to SPLIT-1           |            |
 |        |             |    SPLIT to CICE             |            |
 +------------------------------------------------------------------+
 | 4      | NCICS       | The NCICS and NCICE fields   | Integer    |
 |        |             | are used on the RESIZE       |            |
 |        |             | operation to specify how the |            |
 |        |             | CIC range for existing       |            |
 |        |             | routing key should be        |            |
 |        |             | modified.  NCICS specifies   |            |
 |        |             | the new value that should    |            |
 |        |             | replace the existing CICS    |            |
 |        |             | value in the routing key.    |            |
 +------------------------------------------------------------------+
 | 4      | NCICE       | The NCICS and NCICE fields   | Integer    |
 |        |             | are used on the RESIZE       |            |
 |        |             | operation to specify how the |            |
 |        |             | CIC range for existing       |            |
 |        |             | routing key should be        |            |
 |        |             | modified.  NCICE specifies   |            |
 |        |             | the new value that should    |            |
 |        |             | replace the existing CICE    |            |
 |        |             | value in the routing key.    |            |
 +------------------------------------------------------------------+
  Table 15: Message Data Structure CIC based Routing Key Operations
 The following table indicates the Required (R), or Not Applicable
 (NA) status for each field of the message data structure in Table 15
 based on the RKRP Operation field.  As mentioned previously, unused
 fields (those marked NA) should be initialized to 0 by the sender and
 ignored by the receiver.

Sprague, et al. Informational [Page 71] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

 +------------------------------------------------------------------+
 |      Operation  | ENTER | DELETE | SPLIT | RESIZE | ENTER/DELETE |
 |                 | (ISUP,| (ISUP, | (ISUP,| (ISUP, | PARTIAL DPC  |
 |                 | QBICC,| QBICC, | QBICC,| QBICC, | SI OPC KEY   |
 | Field           | TUP)  | TUP)   | TUP)  | TUP)   |              |
 +------------------------------------------------------------------+
 | Request/Reply   | R     | R      | R     | R      | R            |
 +------------------------------------------------------------------+
 | Success/Failure | R     | R      | R     | R      | R            |
 +------------------------------------------------------------------+
 | RKRP Flags      | R     | R      | R     | R      | R            |
 +------------------------------------------------------------------+
 | SI              | R     | R      | R     | R      | R            |
 +------------------------------------------------------------------+
 | DPC             | R     | R      | R     | R      | R            |
 +------------------------------------------------------------------+
 | OPC             | R     | R      | R     | R      | R            |
 +------------------------------------------------------------------+
 | CICS            | R     | R      | R     | R      | NA           |
 +------------------------------------------------------------------+
 | CICE            | R     | R      | R     | R      | NA           |
 +------------------------------------------------------------------+
 | SPLIT CIC       | NA    | NA     | R     | NA     | NA           |
 +------------------------------------------------------------------+
 | NCICS           | NA    | NA     | NA    | R      | NA           |
 +------------------------------------------------------------------+
 | NCICE           | NA    | NA     | NA    | R      | NA           |
 +------------------------------------------------------------------+
 Table 16: Required/Not Applicable Fields for CIC based Routing Keys

4.5.1.1.1.3 SCCP Routing Key Operations

 The data structure used for 'rkrp' messages related to SCCP routing
 keys is presented in the next table.  The data structure below should
 begin at byte 14 of the TALI message as shown in Table 12.

Sprague, et al. Informational [Page 72] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

 +------------------------------------------------------------------+
 | Octets | Field Name  | Description                  | Field Type |
 +------------------------------------------------------------------+
 | 2      | RKRP        | Identifies which 'rkrp'      | Integer    |
 |        | Operation   | operation is desired.        |            |
 +------------------------------------------------------------------+
 | 2      | Request/    | Identifies whether the 'rkrp'| Integer    |
 |        | Reply       | message is a request (from an|            |
 |        |             | IP node to SG) for some type |            |
 |        |             | of 'rkrp' action, or a reply |            |
 |        |             | to a previous request (from  |            |
 |        |             | the SG back to the IP node). |            |
 |        |             | This integer field uses the  |            |
 |        |             | following encodings:         |            |
 |        |             | 0x0000=Request               |            |
 |        |             | 0x0001=Reply.  See Success/  |            |
 |        |             | Failure code for more info.  |            |
 +------------------------------------------------------------------+
 | 2      | Success/    | Provides a success/failure   | Integer    |
 |        | Failure     | indication as part of the    |            |
 |        | Code        | reply back to the IP node    |            |
 |        |             | for each processed request.  |            |
 |        |             | This field is only used when |            |
 |        |             | the Request/Reply field is   |            |
 |        |             | 0x0001.  This field uses the |            |
 |        |             | encodings listed in section  |            |
 |        |             | 5.                           |            |
 +------------------------------------------------------------------+
 | 2      | RKRP flags  | This is a 2 byte bit-field   | Bit-field  |
 |        |             | that provides 16 possible    |            |
 |        |             | flags that can control       |            |
 |        |             | various aspects of the       |            |
 |        |             | operation.                   |            |
 |        |             | Bit 0 - An Override bit is   |            |
 |        |             | used on the ENTER operation  |            |
 |        |             | to control how the socket    |            |
 |        |             | associations for a routing   |            |
 |        |             | key should be manipulated.   |            |
 |        |             | This flag determines if the  |            |
 |        |             | ENTER is to add the given    |            |
 |        |             | socket association in a      |            |
 |        |             | 'load-sharing' mode or if    |            |
 |        |             | the new association should   |            |
 |        |             | replace (Override) all       |            |
 |        |             | existing associations.  This |            |
 |        |             | flag is only examined on     |            |
 |        |             | ENTER operations.            |            |
 |        |             | Bit 0=0, Load Sharing Mode   |            |

Sprague, et al. Informational [Page 73] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

 |        |             | Bit 0=1, Override Mode       |            |
 |        |             | Bits 1-15, currently         |            |
 |        |             | undefined                    |            |
 +------------------------------------------------------------------+
 | 1      | SI          | Service Indicator.  The SI   | Integer    |
 |        |             | field in an SS7 MSU          |            |
 |        |             | identifies the type of       |            |
 |        |             | traffic being carried by the |            |
 |        |             | MSU (0=SNM, 3=SCCP, 5=ISUP,  |            |
 |        |             | etc).  Each application      |            |
 |        |             | routing key must specify a   |            |
 |        |             | specific SI value that it    |            |
 |        |             | relates to.                  |            |
 |        |             | SI should be 3 for SCCP keys.|            |
 +------------------------------------------------------------------+
 | 4      | DPC         | Destination Point Code.  Each| SS7 Point  |
 |        |             | SS7 MSU contains a DPC that  | Code       |
 |        |             | identifies the destination   |            |
 |        |             | for the MSU.  Each           |            |
 |        |             | application routing key must |            |
 |        |             | specify a specific DPC value |            |
 |        |             | that it relates to.          |            |
 +------------------------------------------------------------------+
 | 1      | SSN         | SubSystem Number.  Each SCCP | Integer    |
 |        |             | MSU contains a subsystem     |            |
 |        |             | number that identifies the   |            |
 |        |             | SCCP subsystem that should   |            |
 |        |             | process the MSU.  SCCP       |            |
 |        |             | routing keys must each       |            |
 |        |             | specify a single SSN that    |            |
 |        |             | the application routing key  |            |
 |        |             | relates to.                  |            |
 +------------------------------------------------------------------+
    Table 17: Message Data Structure SCCP Routing Key Operations
 The following table indicates the Required (R), or Not Applicable
 (NA) status for each field of the message data structure in Table 17
 based on the RKRP Operation field.  As mentioned previously, unused
 fields (those marked NA) should be initialized to 0 by the sender and
 ignored by the receiver.

Sprague, et al. Informational [Page 74] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

            +--------------------------------------------+
            |      Operation  | ENTER SCCP | DELETE SCCP |
            | Field           |            |             |
            +--------------------------------------------+
            | Request/Reply   | R          | R           |
            +--------------------------------------------+
            | Success/Failure | R          | R           |
            +--------------------------------------------+
            | RKRP Flags      | R          | R           |
            +--------------------------------------------+
            | SI              | R          | R           |
            +--------------------------------------------+
            | DPC             | R          | R           |
            +--------------------------------------------+
            | SSN             | R          | R           |
            +--------------------------------------------+
    Table 18: Required/Not Applicable Fields for SCCP Routing Keys

4.5.1.1.1.4 DPC-SI, DPC and SI based Routing Key Operations

 The data structure used for 'rkrp' messages related to DPC-SI based
 (either full keys for non-sccp, non-cic based traffic, or partial
 keys for CIC based or SCCP), DPC based (partial key), and SI based
 (partial key) operations is as presented in the next table.  The data
 structure below should begin at byte 14 of the TALI message as shown
 in Table 12.
 +------------------------------------------------------------------+
 | Octets | Field Name  | Description                  | Field Type |
 +------------------------------------------------------------------+
 | 2      | RKRP        | Identifies which 'rkrp'      | Integer    |
 |        | Operation   | operation is desired.        |            |
 +------------------------------------------------------------------+
 | 2      | Request/    | Identifies whether the 'rkrp'| Integer    |
 |        | Reply       | message is a request (from an|            |
 |        |             | IP node to SG) for some type |            |
 |        |             | of 'rkrp' action, or a reply |            |
 |        |             | to a previous request (from  |            |
 |        |             | the SG back to the IP node). |            |
 |        |             | This integer field uses the  |            |
 |        |             | following encodings:         |            |
 |        |             | 0x0000=Request               |            |
 |        |             | 0x0001=Reply.  See Success/  |            |
 |        |             | Failure code for more info.  |            |

Sprague, et al. Informational [Page 75] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

 +------------------------------------------------------------------+
 | 2      | Success/    | Provides a success/failure   | Integer    |
 |        | Failure     | indication as part of the    |            |
 |        | Code        | reply back to the IP node    |            |
 |        |             | for each processed request.  |            |
 |        |             | This field is only used when |            |
 |        |             | the Request/Reply field is   |            |
 |        |             | 0x0001.  This field uses the |            |
 |        |             | encodings from section 5.    |            |
 +------------------------------------------------------------------+
 | 2      | RKRP flags  | This is a 2 byte bit-field   | Bit-field  |
 |        |             | that provides 16 possible    |            |
 |        |             | flags that can control       |            |
 |        |             | various aspects of the       |            |
 |        |             | operation.                   |            |
 |        |             | Bit 0 - An Override bit is   |            |
 |        |             | used on the ENTER operation  |            |
 |        |             | to control how the socket    |            |
 |        |             | associations for a routing   |            |
 |        |             | key should be manipulated.   |            |
 |        |             | This flag determines if the  |            |
 |        |             | ENTER is to add the given    |            |
 |        |             | socket association in a      |            |
 |        |             | 'load-sharing' mode or if    |            |
 |        |             | the new association should   |            |
 |        |             | replace (Override) all       |            |
 |        |             | existing associations.  This |            |
 |        |             | flag is only examined on     |            |
 |        |             | ENTER operations.            |            |
 |        |             | Bit 0=0, Load Sharing Mode   |            |
 |        |             | Bit 0=1, Override Mode       |            |
 |        |             | Bits 1-15, currently         |            |
 |        |             | undefined                    |            |
 +------------------------------------------------------------------+
 | 1      | SI          | Service Indicator.  The SI   | Integer    |
 |        |             | field in an SS7 MSU          |            |
 |        |             | identifies the type of       |            |
 |        |             | traffic being carried by the |            |
 |        |             | MSU (0=SNM, 3=SCCP, 5=ISUP,  |            |
 |        |             | etc).  Each application      |            |
 |        |             | routing key must specify a   |            |
 |        |             | specific SI value that it    |            |
 |        |             | relates to.                  |            |
 +------------------------------------------------------------------+

Sprague, et al. Informational [Page 76] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

 | 4      | DPC         | Destination Point Code.  Each| SS7 Point  |
 |        |             | SS7 MSU contains a DPC that  | Code       |
 |        |             | identifies the destination   |            |
 |        |             | for the MSU.  Each           |            |
 |        |             | application routing key must |            |
 |        |             | specify a specific DPC value |            |
 |        |             | that it relates to.          |            |
 +------------------------------------------------------------------+
 Table 19: Message Data Structure DPC/SI, DPC and SI based Routing
           Key Operations
 The following table indicates the Required (R), or Not Applicable
 (NA) status for each field of the message data structure in Table 19
 based on the RKRP Operation field.  As mentioned previously, unused
 fields (those marked NA) should be initialized to 0 by the sender and
 ignored by the receiver.
       +-------------------------------------------------------+
       |      Operation  | ENTER/  | ENTER/  | ENTER/ | ENTER/ |
       |                 | DELETE  | DELETE  | DELETE | DELETE |
       |                 | OTHER   | DPC-SI  | DPC    | SI     |
       | Field           | MTP3 SI | PARTIAL | ONLY   | ONLY   |
       +-------------------------------------------------------+
       | Request/Reply   | R       | R       | R      | R      |
       +-------------------------------------------------------+
       | Success/Failure | R       | R       | R      | R      |
       +-------------------------------------------------------+
       | RKRP Flags      | R       | R       | R      | R      |
       +-------------------------------------------------------+
       | SI              | R       | R       | NA     | R      |
       +-------------------------------------------------------+
       | DPC             | R       | R       | R      | NA     |
       +-------------------------------------------------------+
       Table 20: Required/Not Applicable Fields for DPC/SI, DPC
                 and SI based Routing Keys

4.5.1.1.1.5 Default Routing Key Operations

 The data structure used for 'rkrp' messages related to entering and
 deleting a default routing key is as presented in the next table.
 The data structure below should begin at byte 14 of the TALI message
 as shown in Table 12.

Sprague, et al. Informational [Page 77] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

 +------------------------------------------------------------------+
 | Octets | Field Name  | Description                  | Field Type |
 +------------------------------------------------------------------+
 | 2      | RKRP        | Identifies which 'rkrp'      | Integer    |
 |        | Operation   | operation is desired.        |            |
 +------------------------------------------------------------------+
 | 2      | Request/    | Identifies whether the 'rkrp'| Integer    |
 |        | Reply       | message is a request (from an|            |
 |        |             | IP node to SG) for some type |            |
 |        |             | of 'rkrp' action, or a reply |            |
 |        |             | to a previous request (from  |            |
 |        |             | the SG back to the IP node). |            |
 |        |             | This integer field uses the  |            |
 |        |             | following encodings:         |            |
 |        |             | 0x0000=Request               |            |
 |        |             | 0x0001=Reply.  See Success/  |            |
 |        |             | Failure code for more info.  |            |
 +------------------------------------------------------------------+
 | 2      | Success/    | Provides a success/failure   | Integer    |
 |        | Failure     | indication as part of the    |            |
 |        | Code        | reply back to the IP node    |            |
 |        |             | for each processed request.  |            |
 |        |             | This field is only used when |            |
 |        |             | the Request/Reply field is   |            |
 |        |             | 0x0001.  This field uses the |            |
 |        |             | encodings listed in section  |            |
 |        |             | 5.                           |            |
 +------------------------------------------------------------------+
 | 2      | RKRP flags  | This is a 2 byte bit-field   | Bit-field  |
 |        |             | that provides 16 possible    |            |
 |        |             | flags that can control       |            |
 |        |             | various aspects of the       |            |
 |        |             | operation.                   |            |
 |        |             | Bit 0 - An Override bit is   |            |
 |        |             | used on the ENTER operation  |            |
 |        |             | to control how the socket    |            |
 |        |             | associations for a routing   |            |
 |        |             | key should be manipulated.   |            |
 |        |             | This flag determines if the  |            |
 |        |             | ENTER is to add the given    |            |
 |        |             | socket association in a      |            |
 |        |             | 'load-sharing' mode or if    |            |
 |        |             | the new association should   |            |
 |        |             | replace (Override) all       |            |
 |        |             | existing associations.  This |            |
 |        |             | flag is only examined on     |            |
 |        |             | ENTER operations.            |            |
 |        |             | Bit 0=0, Load Sharing Mode   |            |

Sprague, et al. Informational [Page 78] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

 |        |             | Bit 0=1, Override Mode       |            |
 |        |             | Bits 1-15, currently         |            |
 |        |             | undefined                    |            |
 +------------------------------------------------------------------+
      Table 21: Message Data Structure for Default Routing Keys
 The following table indicates the Required (R), or Not Applicable
 (NA) status for each field of the message data structure in Table 21
 based on the RKRP Operation field.  As mentioned previously, unused
 fields (those marked NA) should be initialized to 0 by the sender and
 ignored by the receiver.
            +-------------------------------------+
            |      Operation  | ENTER   | DELETE  |
            | Field           | DEFAULT | DEFAULT |
            +-------------------------------------+
            | Request/Reply   | R       | R       |
            +-------------------------------------+
            | Success/Failure | R       | R       |
            +-------------------------------------+
            | RKRP Flags      | R       | R       |
            +-------------------------------------+
    Table 22: Required/Not Applicable Fields for Default Routing Keys

4.5.1.1.1.6 Support for Multiple RKRP Registration Operations

 The intent of support for multiple RKRP operations within a single
 TALI message (opcode = 'mgmt', primitive = 'rkrp') is to decrease the
 message count and byte overhead on network transmission when
 performing massive registration sequences.
 This functionality is added by 2 mechanisms:
  • a new RKRP operation (0X001B, MULTIPLE REGISTRATIONS SUPPORT) is

defined. This operation is meant to be used in a query/reply

    manner to determine if the far end supports multiple RKRP
    registrations per TALI message before using such capability.
  • The basic 'rkrp' message structure is extended to allow multiple

rkrp operations to follow one another in a tali message.

4.5.1.1.1.6.1 Multiple Registrations Support

 A new RKRP operation and accompanying data structure are defined to
 determine if a far end device supports multiple RKRP registration
 operations per TALI message.

Sprague, et al. Informational [Page 79] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

 The data structure used for the 'multiple registrations support'
 operation is as presented in the next table.  The data structure
 below should begin at byte 14 of the TALI message as shown in Table
 12.
 +------------------------------------------------------------------+
 | Octets | Field Name  | Description                  | Field Type |
 +------------------------------------------------------------------+
 | 2      | RKRP        | Identifies which 'rkrp'      | Integer    |
 |        | Operation   | operation is desired.        |            |
 +------------------------------------------------------------------+
 | 2      | Request/    | Identifies whether the 'rkrp'| Integer    |
 |        | Reply       | message is a request (from an|            |
 |        |             | IP node to SG) for some type |            |
 |        |             | of 'rkrp' action, or a reply |            |
 |        |             | to a previous request (from  |            |
 |        |             | the SG back to the IP node). |            |
 |        |             | This integer field uses the  |            |
 |        |             | following encodings:         |            |
 |        |             | 0x0000=Request               |            |
 |        |             | 0x0001=Reply.  See Success/  |            |
 |        |             | Failure code for more info.  |            |
 +------------------------------------------------------------------+
 | 2      | Success/    | Provides a success/failure   | Integer    |
 |        | Failure     | indication as part of the    |            |
 |        | Code        | reply back to the IP node    |            |
 |        |             | for each processed request.  |            |
 |        |             | This field is only used when |            |
 |        |             | the Request/Reply field is   |            |
 |        |             | 0x0001.  This field uses the |            |
 |        |             | encodings listed in section  |            |
 |        |             | 5.                           |            |
 +------------------------------------------------------------------+
 | 4      | Operations  | This field is used by the    | Integer    |
 |        | Per Message | reply to tell the requester  |            |
 |        |             | the maximum # of RKRP        |            |
 |        |             | registration operations per  |            |
 |        |             | TALI message that are        |            |
 |        |             | supported by the             |            |
 |        |             | implementation.              |            |
 |        |             | * This field should be set   |            |
 |        |             |   to 0 when the request/     |            |
 |        |             |   reply field is set to      |            |
 |        |             |   Request.                   |            |
 |        |             | * This field should be set to|            |
 |        |             |   the Maximum # of operations|            |
 |        |             |   per TALI message that a    |            |
 |        |             |   TALI implementation is     |            |

Sprague, et al. Informational [Page 80] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

 |        |             |   willing to support when the|            |
 |        |             |   request/reply field is set |            |
 |        |             |   to Reply.                  |            |
 +------------------------------------------------------------------+
  Table 23: Message Data Structure for Multiple Registrations Support
            Operation
 The following table indicates the Required (R), or Not Applicable
 (NA) status for each field of the message data structure above.  As
 mentioned previously, unused fields (those marked NA) should be
 initialized to 0 by the sender and ignored by the receiver.
         +-------------------------------------------------+
         |      Operation  | MULTIPLE      | MULTIPLE      |
         |                 | REGISTRATIONS | REGISTRATIONS |
         |                 | SUPPORT       | SUPPORT       |
         | Field           | REQUEST       | REPLY         |
         +-------------------------------------------------+
         | Request/Reply   | R             | R             |
         +-------------------------------------------------+
         | Success/Failure | R             | R             |
         +-------------------------------------------------+
         | Operations Per  | R             | R             |
         | Message         |               |               |
         +-------------------------------------------------+
  Table 24: Required/Not Applicable Fields for Multiple Registrations
            Support Operation

4.5.1.1.1.6.2 Multiple RKRP Operations in a Single Message

 After using the MULTIPLE REGISTRATIONS SUPPORT operation to determine
 that the far end supports multiple RKRP operations per TALI message,
 a device wishing to use this functionality can begin sending more
 than 1 registration request/reply per message.  To do so, the basic
 message structure for an 'mgmt' opcode (presented in Table 12) can be
 extended so that each operation directly follows the previous
 operation in the TALI message.  An example showing a TALI message
 with 3 RKRP operations in it would look as follows:

Sprague, et al. Informational [Page 81] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

 +------------------------------------------------------------------+
 | Octets | Field Name  | Description                               |
 +------------------------------------------------------------------+
 | 0..3   | SYNC        | 'TALI'                                    |
 +------------------------------------------------------------------+
 | 4..7   | OPCODE      | 'mgmt'                                    |
 +------------------------------------------------------------------+
 | 8..9   | LENGTH      | Length. The length should be set such that|
 |        |             | all (3 in this example) operations are    |
 |        |             | accounted for.                            |
 +------------------------------------------------------------------+
 | 10..13 | Primitive   | 'rkrp'                                    |
 +------------------------------------------------------------------+
 | 14..17 | Primitive   | The fisrt operation field identifies a    |
 |        | Operation   | specific rkrp operation to be performed.  |
 |        | #1          |                                           |
 +------------------------------------------------------------------+
 | 18..x  | Message     | The length of the message data (and the   |
 |        | Data for    | interpretation of those bytes) for        |
 |        | Operation   | operation #1 depends on the message data  |
 |        | #1          | required for rkrp operation #1            |
 +------------------------------------------------------------------+
 | x+1..  | Primitive   | The fisrt operation field identifies a    |
 |   x+4  | Operation   | specific rkrp operation to be performed.  |
 |        | #2          |                                           |
 +------------------------------------------------------------------+
 | x+5..y | Message     | The length of the message data (and the   |
 |        | Data for    | interpretation of those bytes) for        |
 |        | Operation   | operation #2 depends on the message data  |
 |        | #2          | required for rkrp operation #2            |
 +------------------------------------------------------------------+
 | y+1..  | Primitive   | The fisrt operation field identifies a    |
 |   y+4  | Operation   | specific rkrp operation to be performed.  |
 |        | #3          |                                           |
 +------------------------------------------------------------------+
 | y+5..z | Message     | The length of the message data (and the   |
 |        | Data for    | interpretation of those bytes) for        |
 |        | Operation   | operation #3 depends on the message data  |
 |        | #3          | required for rkrp operation #3            |
 +------------------------------------------------------------------+
    Table 25: Message Structure for 'mgmt' opcode with multiple
              'rkrp' operations in 1 TALI Message

Sprague, et al. Informational [Page 82] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

 It should be reiterated that in order to avoid unpredictable
 behavior, a node using the 'multiple registrations per TALI msg'
 capability must be sure the far end device supports the capability.
 The only way to be sure of this is to successfully send a MULTIPLE
 REGISTRATION SUPPORT request and receive a MULTIPLE REGISTRATION
 SUPPORT reply.

4.5.1.2 MTP3 Primitive (mtpp)

 The 'mtpp' primitive allows IP nodes to receive status regarding
 point code (un)availability and congestion levels.  These messages
 provide information similar to the TFP/TFA (TransFer Prohibited and
 TransFer Allowed), TFC (TransFer Congested) and RCT (Route Congestion
 Test) messages that are encoded as SS7 SNM (Signaling Network
 Management) MSUs in traditional SS7 networks.  The 'mtp3 primitives'
 allow this status information to be transferred in-band, via TALI
 messages, to the IP nodes.
 The specific information provided in each 'mtpp' message is indicated
 via an 'MTPP Operation' field.  These capabilities provided by the
 various MTPP Operation fields include:
  • POINT CODE UNAVAILABLE: This primitive operation announces that an

SS7 Point Code is Unavailable (ie: the SG has NO route available

    to send traffic for the destination).  The PT CODE field indicates
    which SS7 Pt Code this operation is concerned with.
  • POINT CODE AVAILABLE: This primitive operation announces that an

SS7 Point Code is Available (ie: the SG has SOME route available

    to send traffic for the destination).  The PT CODE field indicates
    which SS7 Pt Code this operation is concerned with.
  • REQUEST FOR POINT CODE STATUS: This primitive operation provides a

way for one end of the connection to poll the other end for the

    available/unavailable status of a specific SS7 pt code.  For
    instance, the IP node can poll the SG - Can you send traffic
    successfully for the destination indicated?  The receiver of the
    request will reply to the request with either a point code
    available or pt code unavailable primitive respectively.
  • CLUSTER UNAVAILABLE: This primitive operation announces that an

entire Cluster of SS7 Point Codes (ex: 10-10-*) are Unavailable

    (ie: the SG has NO route available to send traffic for any of the
    destinations in that cluster).  The PT CODE field indicates which
    SS7 Cluster Pt Code this operation is concerned with.
  • CLUSTER AVAILABLE: This primitive operation announces that at

least 1 SS7 Point Code within a cluster is Available (ie: the SG

Sprague, et al. Informational [Page 83] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

    has SOME route available to send traffic for at least 1 of the
    destinations in that cluster).  The PT CODE field indicates which
    SS7 Cluster Pt Code this operation is concerned with.
  • REQUEST FOR CLUSTER STATUS: This primitive operation provides a

way for one end of the connection to poll the other end for the

    available/unavailable status of a cluster of SS7 pt codes.  For
    instance, the IP node can poll the SG - Can you send traffic
    successfully for any of the destinations in the cluster?  The
    receiver of the request will reply to the request with either a
    cluster available or cluster unavailable primitive respectively.
  • CONGESTED DESTINATION: This primitive operation announces that the

path towards an SS7 Point Code is Congested. The PT CODE field

    indicates which SS7 Pt Code this operation is concerned with.  The
    CONGESTION LEVEL field indicates the severity of the congestion.
  • REQUEST FOR CONGESTION STATUS: This primitive operation provides a

way for one end of the connection to poll the other end for the

    congestion status of an SS7 pt code.  For instance, the IP node
    can poll the SG - Is the path to the specified destination still
    congested?  This request is used to abate congestion towards an
    SS7 destination.
  • As an implementation note: Upon receiving this request, the SG

will generate and send a Route Congestion Test (RCT), SS7

       Network Management Message with a priority set to match the
       congestion level in the request.  The RCT is sent towards the
       SS7 destination.  If the SS7 destination is still congested,
       the RCT will result an SS7 Transfer Controlled (TFC) arriving
       back at the SG, which will be converted into a CONGESTED
       DESTINATION primitive and sent on to the IP node.
  • USER PART UNAVAILABLE: SS7 nodes send User Part Unavailable

messages when a user part that is mounted on a node is no longer

    available for service.  This primitive operation provides a way
    for an IP Node to receive the same information as the SS7 UPU
    message.
 In order to simplify the implementation, a single data structure is
 defined to be used for all of the 'mtpp' operations.  Depending on
 the 'mtpp operation', some of the fields will be required, and some
 of the fields will not be applicable for each MTPP message.  Unused
 fields should be initialized to 0 by the sender and ignored by the
 receiver.  The data structure used for 'mtpp' messages is as
 presented in the next table.  The data structure below should begin
 at byte 14 of the TALI message as shown in Table 12.

Sprague, et al. Informational [Page 84] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

 +------------------------------------------------------------------+
 | Octets | Field Name  | Description                  | Field Type |
 +------------------------------------------------------------------+
 | 2      | MTPP        | Identifies which 'mtpp'      | Integer    |
 |        | Operation   | operation/capability is      |            |
 |        |             | provided in this message.    |            |
 |        |             | This integer field uses the  |            |
 |        |             | following encodings:         |            |
 |        |             | 0x0001 = PC Unavailable      |            |
 |        |             | 0x0002 = PC Available        |            |
 |        |             | 0x0003 = Request for PC      |            |
 |        |             |          Status              |            |
 |        |             | 0x0004 = Cluster Unavailable |            |
 |        |             | 0x0005 = Cluster Available   |            |
 |        |             | 0x0006 = Request for Cluster |            |
 |        |             |          Status              |            |
 |        |             | 0x0007 = Congested           |            |
 |        |             |          Destination, w/Cong |            |
 |        |             |          Level               |            |
 |        |             | 0x0008 = Request for         |            |
 |        |             |          Congestion Status   |            |
 |        |             | 0x0009 = User Part           |            |
 |        |             |          Unavailable         |            |
 +------------------------------------------------------------------+
 | 4      | Concerned   | Identifies the SS7 Point Code| SS7 Point  |
 |        | Point       | that is relevant to the mtpp | Code       |
 |        | Code        | operation.  The mtpp         |            |
 |        |             | operation is concerning this |            |
 |        |             | point code (or cluster).     |            |
 +------------------------------------------------------------------+
 | 4      | Source      | This field is only used on   | SS7 Point  |
 |        | Point       | the 'Congested Destination'  | Code       |
 |        | Code        | and 'Request for Congestion  |            |
 |        |             | Status' operations.          |            |
 |        |             | * When used in an 'Congestion|            |
 |        |             |   Destination' operation,    |            |
 |        |             |   this field contains the Pt |            |
 |        |             |   Code of the Source of the  |            |
 |        |             |   traffic that was           |            |
 |        |             |   experiencing congestion as |            |
 |        |             |   it made its way to the     |            |
 |        |             |   Concerned Pt Code.  In     |            |
 |        |             |   terms of the original SS7  |            |
 |        |             |   MSUs (the TransFer         |            |
 |        |             |   Controlled MSU) that       |            |
 |        |             |   provided congestion        |            |
 |        |             |   information, the CPC of the|            |
 |        |             |   TFC is the 'Concerned Point|            |

Sprague, et al. Informational [Page 85] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

 |        |             |   Code' of the resulting MTPP|            |
 |        |             |   primitive and the DPC of   |            |
 |        |             |   the TFC is the 'Source     |            |
 |        |             |   Point Code' of the         |            |
 |        |             |   resulting MTPP primitive.  |            |
 |        |             | * When used in an 'Request   |            |
 |        |             |   for Congestion Status'     |            |
 |        |             |   operation, this field      |            |
 |        |             |   indicates which Source Pt  |            |
 |        |             |   Code is trying to abate the|            |
 |        |             |   congestion of the concerned|            |
 |        |             |   Pt Code.  In terms of the  |            |
 |        |             |   original SS7 MSUs (the     |            |
 |        |             |   Route Congestion Test MSU) |            |
 |        |             |   that is used to poll for   |            |
 |        |             |   congestion, the DPC of the |            |
 |        |             |   RCT is the 'Concerned Point|            |
 |        |             |   Code' of the MTPP primitive|            |
 |        |             |   and the OPC of the RCT is  |            |
 |        |             |   the 'Source Point Code' of |            |
 |        |             |   the MTPP primitive.        |            |
 +------------------------------------------------------------------+
 | 2      | Congestion  | This field is used on the    | Integer    |
 |        | Level       | 'Congested Destination' and  |            |
 |        |             | 'Request for Congestion      |            |
 |        |             | Status' operations to        |            |
 |        |             | indicate the congestion level|            |
 |        |             | of the destination.  This    |            |
 |        |             | integer field uses the       |            |
 |        |             | following encodings:         |            |
 |        |             | 0x0000 = Congestion Level 0  |            |
 |        |             | 0x0001 = Congestion Level 1  |            |
 |        |             | 0x0002 = Congestion Level 2  |            |
 |        |             | 0x0003 = Congestion Level 3  |            |
 +------------------------------------------------------------------+
 | 2      | Cause Code  | This field is used on the    | Integer    |
 |        |             | 'User Part Unavailable'      |            |
 |        |             | operation to indicate the    |            |
 |        |             | Cause Code for why the UPU is|            |
 |        |             | being sent.  This integer    |            |
 |        |             | field uses the following     |            |
 |        |             | encodings:                   |            |
 |        |             | 0x0000 = Cause Unknown       |            |
 |        |             | 0x0001 = User Part Unequipped|            |
 |        |             | 0x0002 = User Part           |            |
 |        |             |          Inaccessible        |            |
 +------------------------------------------------------------------+

Sprague, et al. Informational [Page 86] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

 | 2      | User ID     | This field is used on the    | Integer    |
 |        |             | 'User Part Unavailable'      |            |
 |        |             | operation to indicate which  |            |
 |        |             | user part is unavailable. The|            |
 |        |             | User ID field identifies the |            |
 |        |             | type of traffic that was     |            |
 |        |             | unavailable (0=SNM, 3=SCCP,  |            |
 |        |             | 5=ISUP, etc).                |            |
 +------------------------------------------------------------------+
  Table 26: Message Data Structure for use with the 'mtpp' Primitive
 The following table indicates the Required (R), or Not Applicable
 (NA) status for each field of the message data structure in Table 26
 based on the MTPP Operation field.  As mentioned previously, unused
 fields (those marked NA) should be initialized to 0 by the sender and
 ignored by the receiver.

Sprague, et al. Informational [Page 87] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

 +------------------------------------------------------------------+
 |          Field  | Concerned | Source | Congestion | Cause | User |
 |                 | Point     | Point  |  Level     | Code  | ID   |
 | Operation       | Code      | Code   |            |       |      |
 +------------------------------------------------------------------+
 | PC Unavailable  | R         | NA     | NA         | NA    | NA   |
 +------------------------------------------------------------------+
 | PC Available    | R         | NA     | NA         | NA    | NA   |
 +------------------------------------------------------------------+
 | Request for PC  | R         | NA     | NA         | NA    | NA   |
 | Status          |           |        |            |       |      |
 +------------------------------------------------------------------+
 | Cluster         | R         | NA     | NA         | NA    | NA   |
 | Unavailable     |           |        |            |       |      |
 +------------------------------------------------------------------+
 | Cluster         | R         | NA     | NA         | NA    | NA   |
 | Available       |           |        |            |       |      |
 +------------------------------------------------------------------+
 | Request for     | R         | NA     | NA         | NA    | NA   |
 | Cluster Status  |           |        |            |       |      |
 +------------------------------------------------------------------+
 | Congested       |           |        |            |       |      |
 | Destination w/  | R         | R      | R          | NA    | NA   |
 | Cong. Level     |           |        |            |       |      |
 +------------------------------------------------------------------+
 | Request for     |           |        |            |       |      |
 | Congestion      | R         | R      | R          | NA    | NA   |
 | Status          |           |        |            |       |      |
 +------------------------------------------------------------------+
 | User Part       | R         | NA     | NA         | R     | R    |
 | Unavailable     |           |        |            |       |      |
 +------------------------------------------------------------------+
    Table 27: Required/Not Applicable Fields for MTPP Operations

4.5.1.3 Socket Option Registration Primitive (sorp)

 The 'sorp' primitive allows IP nodes to set various options on a
 socket by socket basis.  This allows the IP node some control over
 the communication that will occur across the TALI connection.  The
 'sorp' primitives allows this socket option control to be transferred
 in-band, via TALI messages, to the IP nodes.
 The SORP primitives capabilities that are available to the IP device
 in SG are as follows:

Sprague, et al. Informational [Page 88] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

  • Set SORP Flags: Used to set the flags bit field. The receiver of

this message should store the bit settings indicated in the SORP

    Flag field.
  • Request Current SORP Flags Settings: Used to poll for the status

of the bit field options. The receiver of this message should

    send a Reply w/ Current SORP Flag settings.
  • Reply w/ Current SORP Flag Settings: Used to reply to a poll,

indicating the current bit field settings to the far end.

 As of TALI 2.0, each socket option is stored as a bit in a 32 bit
 bit-field.  Each bit in the field indicates the setting for 1 option.
 A bit field with a 0 value indicates the option is DISABLED.  A bit
 field with a 1 value indicates the option is ENABLED.  The following
 options are currently supported:
  • ENABLE/DISABLE BROADCAST PHASE MTPP PRIMITIVES: Traditional STPs

send Broadcast Phase TFPs and TFAs to all adjacent nodes when the

    point code availability changes for destinations in the STP's SS7
    routing table.  These Broadcast Phase TFA/TFP SS7 messages are
    converted into TALI mtpp primitives by SG nodes such as the SG.
    The ENABLE/DISABLE BROADCAST PHASE MTPP PRIMITIVES options allow
    each IP node to tell the remote end whether the IP node wants to
    receive the mtpp primitives that result from SS7 broadcast phase
    messages.
  • As an implementation note: In the SG, each defined socket has a

flag, 'enable_broadcast_phase_primitives', which is initialized

       to FALSE each time the socket connects.  The IP node should
       send the ENABLE BROADCAST PHASE MESSAGES operation to the SG to
       announce that it wants to receive unsolicited status changes
       for a particular socket.  As the SG is determining where to
       send broadcast phase TFAs/TFPs, it will interrogate the
       'enable_broadcast_phase_primitives' flag for each socket on
       that socket.
  • ENABLE/DISABLE RESPONSE METHOD MTPP PRIMITIVES: Traditional STPs

send Response Method TFPs to adjacent nodes when the adjacent

    nodes continue to send MSUs to the STP that can not be delivered
    (ie: the STP has told the adjacent node that a destination is
    Unavailable, but the adjacent node continues to send traffic
    destined for that unavailable DPC to the STP).  These Response
    Method messages are sent in response to MSUs that are received at
    the STP.  These Response Method TFP messages are converted into
    TALI mtpp primitives by SG nodes such as the SG.  The
    ENABLE/DISABLE RESPONSE METHOD MTPP PRIMITIVES options allow each
    IP node to tell the remote end whether the IP node wants to

Sprague, et al. Informational [Page 89] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

    receive the mtpp primitives that result from SS7 response method
    messages.  In addition to response method TFPs, 2 other SS7
    Network Management messages, namely TFCs (transfer controlled) and
    UPUs (user part unavailable), fall into this RESPONSE METHOD
    grouping.  TFCs and UPUs are similar to response method TFPs due
    to the fact that a previous action by the IP Node (sending traffic
    toward some destination) has caused a response method event back
    to the IP Node.  The primary difference between response method
    TFPs versus response method TFCs/UPUs is that the response method
    TFP is converted to an MTPP primitive and sent back to only the
    original socket, while response method TFCs/UPUs may need to be
    replicated to multiple sockets (after being converted to mtpp
    primitives) since there is no way to tell which socket caused the
    response method event.
  • As an implementation node: In the SG, each defined socket has a

flag, 'enable_response_method_primitives', which is initialized

       to FALSE each time the socket connects.  The IP node should
       send the ENABLE RESPONSE METHOD MTPP PRIMITIVES operation to
       the SG to announce that it wants to receive response method
       TFPs when appropriate for a particular socket.  Before the SG
       sends a response method TFP (converted to a mtpp primitive)
       back to an IP node, the SG will interrogate the
       'enable_response_method_primitives' flag for that socket and
       only perform the send if the flag allows it.
  • ENABLE/DISABLE NORMALIZED SCCP: Version 1.0 of TALI specified that

the 'sccp' TALI opcode must be used on point to multipoint

    connections in order to transmit SCCP MSUs between the SG and IP
    nodes.  When using the 'sccp' opcode, the MTP3 header portion of
    the original SS7 MSU was stripped from the MSU and was NOT part of
    the data transmitted across the TALI connection.  The sender of
    the 'sccp' TALI message was responsible for duplicating the
    DPC/OPC fields from the MTP3 header into appropriate fields in the
    SCCP portion of the message (into the Called/Calling Party Address
    Pt Code fields) before sending as a 'sccp' opcode.  This option
    provides a way to send SCCP MSUs across TALI point to multipoint
    connections that includes the MTP3 header as part of the data
    transmitted, and does NOT involve any modification to the original
    SS7 SCCP MSU.  When the ENABLE NORMALIZED SCCP primitive is
    received, SCCP MSUs should be sent across the TALI interface using
    the 'mtp3' opcode.  This transmission should include the entire
    MTP3 header + the sccp portion of the original MSU.  No
    modification of the original SS7 MSU should occur.  When the
    DISABLE NORMALIZED SCCP primitive is received, SCCP MSUs should be
    sent across the TALI interface using the 'sccp' opcode as
    specified in version 1.0 of TALI.

Sprague, et al. Informational [Page 90] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

  • ENABLE/DISABLE NORMALIZED ISUP: Version 1.0 of TALI specified that

the 'isot' TALI opcode must be used on point to multipoint

    connections in order to transmit ISUP MSUs between the SG and IP
    nodes.  When using the 'isot' opcode, the original SS7 MSU,
    including the MTP3 header portion, was transmitted in a 'isot'
    TALI message.  This option indicates that the far end would prefer
    to receive ISUP MSUs using the 'mtp3' TALI opcode as opposed to
    the 'isot' opcode.  When the option is ENABLED, the 'mtp3' opcode
    is used to transmit ISUP MSUs, including the MTP3 header, across
    the TALI connection.  When the option is DISABLED, the 'isot'
    opcode is used as in TALI Release 1.0.
 The data structure used for 'sorp' messages is as presented in the
 next table.  The data structure below should begin at byte 14 of the
 TALI message as shown in Table 12.

Sprague, et al. Informational [Page 91] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

 +------------------------------------------------------------------+
 | Octets | Field Name  | Description                  | Field Type |
 +------------------------------------------------------------------+
 | 2      | SORP        | Identifies which 'sorp'      | Integer    |
 |        | Operation   | operation/capability is      |            |
 |        |             | provided in this message.    |            |
 |        |             | This integer field uses the  |            |
 |        |             | following encodings:         |            |
 |        |             | 0x0001 = Set SORP Flags      |            |
 |        |             | 0x0002 = Request Current     |            |
 |        |             |          SORP Flags Settings |            |
 |        |             | 0x0003 = Reply w/ Current    |            |
 |        |             |          SORP Flag Settings  |            |
 +------------------------------------------------------------------+
 | 2      | SORP Flags  | A 4 byte bit-field that uses | Bit-Field  |
 |        |             | each bit as an enabled/      |            |
 |        |             | disabled flag for a          |            |
 |        |             | particular socket option.    |            |
 |        |             | Bit x = 0 indicates the      |            |
 |        |             |         option is DISABLED.  |            |
 |        |             | Bit x = 1 indicates the      |            |
 |        |             |         option is ENABLED.   |            |
 |        |             | The assignments for each BIT |            |
 |        |             | are as follows:              |            |
 |        |             | Bit 0 = Broadcast Phase MTPP |            |
 |        |             |         Primitives           |            |
 |        |             | Bit 1 = Response Method MTPP |            |
 |        |             |         Primitives           |            |
 |        |             | Bit 2 = Normalized SCCP      |            |
 |        |             | Bit 3 = Normalized ISUP      |            |
 +------------------------------------------------------------------+
   Table 28: Message Data Structure to be used for 'sorp' Primitive

4.5.2 Extended Service Message (xsrv)

 The Extended Service, 'xsrv', opcode is added to the TALI 2.0
 protocol to lay the groundwork for providing a means to transport
 other types of service traffic (beyond 'sccp', 'isot', 'mtp3', and
 'saal') in future revisions of this protocol without having to define
 a new opcode as each new service type is identified and added.  The
 PRIMITIVE field will uniquely identify each new service type as they
 are added.  It is envisioned that some 'xsrv' messages can be
 received and processed in any of the TALI NEx-FEx state, while some
 other 'xsrv' messages can only be received and processed in the NEA-
 FEA state (such as Service data in version 1.0 of TALI).

Sprague, et al. Informational [Page 92] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

 There are no specific PRIMITIVES defined for this opcode in this
 release.  It is expected that some new service messages will be added
 in the future.  This opcode provides for grouping of the new service
 data types.
 +------------------------------------------------------------------+
 | Octets | Field Name  | Description                               |
 +------------------------------------------------------------------+
 | 0..3   | SYNC        | 'TALI'                                    |
 +------------------------------------------------------------------+
 | 4..7   | OPCODE      | 'xsrv'                                    |
 +------------------------------------------------------------------+
 | 8..9   | LENGTH      | Length                                    |
 +------------------------------------------------------------------+
 | 10..13 | Primitive   | To be determined                          |
 +------------------------------------------------------------------+
 | 14..   | Message     | To be determined                          |
 |   2000 | Data        |                                           |
 +------------------------------------------------------------------+

4.5.3 Special Message (spcl)

 The Special Message, 'spcl', opcode is added to the TALI 2.0 protocol
 to provide a way for vendors to build special services into their
 TALI implementations that are only activated when the implementation
 is connected to other equipment implementing the same special
 services.  'spcl' messages can be received and processed in any of
 the TALI NEx-FEx states.  This opcode is intended to provide a
 general means to discover more information regarding who the TALI
 session is connected to, and to provide means to enable special
 features based on the vendor/implementation on the far end.
 As part of the 2.0 specification, 4 primitives are initially defined
 for this opcode:
  • 'smns' - Special Messages Not Supported.
  • 'qury' - Query.
  • 'rply' - Reply.
  • 'usim' - UnSolicited Information Message.
 Additional primitives can be added in future versions of the TALI
 protocol.

Sprague, et al. Informational [Page 93] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

 +------------------------------------------------------------------+
 | Octets | Field Name  | Description                               |
 +------------------------------------------------------------------+
 | 0..3   | SYNC        | 'TALI'                                    |
 +------------------------------------------------------------------+
 | 4..7   | OPCODE      | 'spcl'                                    |
 +------------------------------------------------------------------+
 | 8..9   | LENGTH      | Length                                    |
 +------------------------------------------------------------------+
 | 10..13 | Primitive   | 'smns' - special messages not supported   |
 |        |             | 'qury' - query                            |
 |        |             | 'rply' - reply                            |
 |        |             | 'usim' - UIM (unsolicited information msg)|
 +------------------------------------------------------------------+
 | 14..X  | Data        | Vendor dependent                          |
 +------------------------------------------------------------------+

4.5.3.1 Special Messages Not Supported (smns)

 This message is sent as a response to a 'spcl' message with a 'qury'
 PRIMITIVE.  A node may send out this message when it wants the Far
 End to know that it does not support 'spcl' messages and wishes not
 to receive them in the future.
 +------------------------------------------------------------------+
 | Octets | Field Name  | Description                               |
 +------------------------------------------------------------------+
 | 0..3   | SYNC        | 'TALI'                                    |
 +------------------------------------------------------------------+
 | 4..7   | OPCODE      | 'spcl'                                    |
 +------------------------------------------------------------------+
 | 8..9   | LENGTH      | Length                                    |
 +------------------------------------------------------------------+
 | 10..13 | Primitive   | 'smns'                                    |
 +------------------------------------------------------------------+

4.5.3.2 Query Message (qury)

 This message can be sent to Query the far end of the connection (ie:
 try to find out more information about the VENDOR, TALI version, or
 other features).  It is expected that each 2.0 implementation would
 respond to a 'qury' with a 'rply'.

Sprague, et al. Informational [Page 94] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

 +------------------------------------------------------------------+
 | Octets | Field Name  | Description                               |
 +------------------------------------------------------------------+
 | 0..3   | SYNC        | 'TALI'                                    |
 +------------------------------------------------------------------+
 | 4..7   | OPCODE      | 'spcl'                                    |
 +------------------------------------------------------------------+
 | 8..9   | LENGTH      | Length                                    |
 +------------------------------------------------------------------+
 | 10..13 | Primitive   | 'qury'                                    |
 +------------------------------------------------------------------+

4.5.3.3 Reply Message (rply)

 The 'rply' message provides a way for a TALI 2.0 implementation to
 identify itself in more detail.  The information included in the
 reply includes:
  • PEC - a 2 byte field that identifies the vendor for the TALI

implemenation.

  • Version Number - a 12 byte field that identifies the TALI version

of the implementation.

  • Other Vendor Specific Data - the format of any remaining data that

a particular vendor wants to provide is specific to each vendor.

 +------------------------------------------------------------------+
 | Octets | Field Name  | Description                               |
 +------------------------------------------------------------------+
 | 0..3   | SYNC        | 'TALI'                                    |
 +------------------------------------------------------------------+
 | 4..7   | OPCODE      | 'spcl'                                    |
 +------------------------------------------------------------------+
 | 8..9   | LENGTH      | Length                                    |
 +------------------------------------------------------------------+
 | 10..13 | Primitive   | 'rply'                                    |
 +------------------------------------------------------------------+
 | 14..15 | PEC         | Private Enterprise Code *                 |
 |        |             | (Vendor ID Number, Integer Field)         |
 +------------------------------------------------------------------+
 | 16..27 | Version     | 'vers xxx.yyy'                            |
 |        | Label       |                                           |
 +------------------------------------------------------------------+
 | 28..?  | Other Vendor| Free Format data area, specific to each   |
 |        | Specific    | vendor                                    |
 |        | Data        |                                           |
 +------------------------------------------------------------------+

Sprague, et al. Informational [Page 95] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

  • See Table 4 for details on the PEC field.

4.5.3.4 Unsolicited Information Message (USIM)

 A 'usim' provides the same information as the 'rply' primitive.  The
 'usim' can be sent at any time by a 2.0 implementation (whereas the
 'rply' should only be sent in reply to a 'qury').
 +------------------------------------------------------------------+
 | Octets | Field Name  | Description                               |
 +------------------------------------------------------------------+
 | 0..3   | SYNC        | 'TALI'                                    |
 +------------------------------------------------------------------+
 | 4..7   | OPCODE      | 'spcl'                                    |
 +------------------------------------------------------------------+
 | 8..9   | LENGTH      | Length                                    |
 +------------------------------------------------------------------+
 | 10..13 | Primitive   | 'usim'                                    |
 +------------------------------------------------------------------+
 | 14..15 | PEC         | Private Enterprise Code *                 |
 |        |             | (Vendor ID Number, Integer Field)         |
 +------------------------------------------------------------------+
 | 16..27 | Version     | 'vers xxx.yyy'                            |
 |        | Label       |                                           |
 +------------------------------------------------------------------+
 | 28..?  | Other Vendor| Free Format data area, specific to each   |
 |        | Specific    | vendor                                    |
 |        | Data        |                                           |
 +------------------------------------------------------------------+

4.6 TALI Timers

 Version 2.0 of the TALI specification does not introduce any new
 timers.  The T1-T4 timers defined previously remain in effect.
 While, it is expected that most implementations wishing to identify
 themselves as 2.0 (or later) would use a non-zero value for T4 - this
 is a not a hard requirement.  The only requirement for identifying
 yourself as 2.0 is to send at least 1 'moni' as per the 2.0 format
 upon connection establishment.

4.7 TALI User Events

 Version 2.0 of the TALI specification does not introduce any new user
 events.  The user events defined in Section 3.4 (mgmt open, mgmt
 close, mgmt allow, mgmt proh, connection established, connection
 lost) remain in effect.

Sprague, et al. Informational [Page 96] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

4.8 TALI States

 Version 2.0 of the TALI specification does not introduce any new TALI
 states.  The TALI states defined in Section 3.6 remain in effect.

4.9 TALI Version 2.0 State Machine

 This section provides the state machine that must be followed by each
 TALI 2.0 implementation in order to be compliant with this
 specification.  As mentioned throughout this document, a 2.0
 implementation is based on several small additions to a 1.0
 implementation and each 2.0 implementation must be willing to inter-
 operate in a backwards compatible mode (a 2.0 implementation
 connected to a 1.0 implementation must fall back to 1.0 features
 only).

4.9.1 State Machine Concepts

 Before presenting the actual state machine, several concepts are
 discussed.

4.9.1.1 General Protocol Rules

 A set of general protocol rules was presented in the 1.0
 specification, in section 3.7.1.1; those rules are still applicable
 to 2.0 implementations.  In addition to those earlier rules, the
 following rules are also applicable to 2.0 nodes:
  • A 2.0 implementation should identify the TALI version it has

implemented via the 'moni' message

  • A 2.0 implementation should process any received 'moni' messages,

attempting to determine the TALI version of the far end. A 2.0

    implementation must use an internal flag, such as
    'far_end_version', to track the TALI version that the far end of
    the connection has implemented.  The 'far_end_version' flag should
    be initialized to version 1.0.
  • A 2.0 implementation should reject/ignore internal requests (from

software layers in it's own product, or requests from the

    management interface for the device) to send TALI messages that
    require 2.0 opcodes when the far end is a 1.0 implementation.  A
    2.0 implementation should only send TALI messages that require new
    2.0 opcodes (mgmt, xsrv, spcl) when it knows the far end is
    capable of processing those opcodes (when 'far_end_version' is 2.0
    or greater).

Sprague, et al. Informational [Page 97] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

  • Upon receiving a TALI message with a 2.0 opcode, a 2.0

implementation should interrogate its 'far_end_flag'; if the far

    end is not 2.0 or greater, the arrival of the message should be
    treated as a Protocol Violation.  If the far end is 2.0 or
    greater, the message should be processed according to the nodes
    2.0 capabilities, or ignored (if the node has chosen not to
    implement any 2.0 functionalities).

4.9.1.2 Graceful Shutdown of a Socket

 The steps to perform a graceful shutdown of each socket were
 presented in the 1.0 specification, in section 3.7.1.2.  Those steps
 are not changed for 2.0 implementations.

4.9.1.3 TALI Protocol Violations

 Each TALI implementation must detect when violations of the TALI
 protocol have occurred and react accordingly.  Protocol violations
 include:
  • Invalid sync code in a received message
  • Invalid opcode in a received message
  • Invalid length field in a received message
  • Not receiving an 'allo' or 'proh', in response to the origination

of a 'test' , before the T2 timer expires

  • Receiving Service Messages on a prohibited socket.
  • TCP Socket errors - Connection Lost
  • Receiving a TALI message with a 2.0 opcode ('mgmt', 'xsrv', '

spcl') from a far end that has not identified itself as a 2.0

    implementation.
 In the state machine that follows, State/Event combinations that
 should be treated as protocol violations are indicated via a 'PV' in
 the state/event cell.  All of the 'PV' events are then processed as
 per the 'Protocol Violation' row in the table.

4.9.2 The State Machine

 Internal Data required for State Machine:
  • boolean sock_allowed. This flag indicate whether the NE is

allowed to carry Service Messages.

Sprague, et al. Informational [Page 98] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

  • Far_end_version. This enumeration should track the TALI version

of the far end of the socket.

 Initial Conditions:
 sock_allowed = FALSE
 far_end_version = 1.0
 state = OOS
 no timers running
 +------------------------------------------------------------------+
 |   State| OOS  |Connecting| NEP-FEP | NEP-FEA | NEA-FEP | NEA-FEA |
 |Event   |      |          |         |         |         |         |
 +------------------------------------------------------------------+
 |T1 Exp. |      |          |Send test|Send test|Send test|Send test|
 |        |      |          |Start T1 |Start T1 |Start T1 |Start T1 |
 |        |      |          |Start T2 |Start T2 |Start T2 |Start T2 |
 +------------------------------------------------------------------+
 |T2 Exp. |      |          |   PV    |   PV    |   PV    |   PV    |
 +------------------------------------------------------------------+
 |T3 Exp. |      |          |   PV    |   PV    |         |         |
 +------------------------------------------------------------------+
 |T4 Exp. |      |          |Send moni|Send moni|Send moni|Send moni|
 |        |      |          |Start T4 |Start T4 |Start T4 |Start T4 |
 +------------------------------------------------------------------+
 |Rcv test|      |          |Send proh|Send proh|Send allo|Send allo|
 +------------------------------------------------------------------+
 |Rcv allo|      |          | Stop T2 | Stop T2 | Stop T2 | Stop T2 |
 |        |      |          | NEP-FEA |         | NEA-FEA |         |
 +------------------------------------------------------------------+
 |Rcv proh|      |          | Stop T2 | Stop T2 | Stop T2 | Stop T2 |
 |        |      |          |Send proa|Send proa|Send proa|Flush or |
 |        |      |          |         | NEP-FEP |         | reroute |
 |        |      |          |         |         |         |Send proa|
 |        |      |          |         |         |         | NEA-FEP |
 +------------------------------------------------------------------+
 |Rcv proa|      |          | Stop T3 | Stop T3 |         |         |
 +------------------------------------------------------------------+
 |Rcv moni|      |          |Update   |Update   |Update   |Update   |
 |        |      |          |'far end |'far end |'far end |'far end |
 |        |      |          |version' |version' |version' |version' |
 |        |      |          |based on |based on |based on |based on |
 |        |      |          |moni     |moni     |moni     |moni     |
 |        |      |          |Convert  |Convert  |Convert  |Convert  |
 |        |      |          | to mona | to mona | to mona | to mona |
 |        |      |          |Send mona|Send mona|Send mona|Send mona|
 +------------------------------------------------------------------+

Sprague, et al. Informational [Page 99] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

 |Rcv mona|      |          |Implemen-|Implemen-|Implemen-|Implemen-|
 |        |      |          |tation   |tation   |tation   |tation   |
 |        |      |          |dependent|dependent|dependent|dependent|
 +------------------------------------------------------------------+
 |Rcv     |      |          |   PV    |If T3 run|   PV    |Process  |
 | Service|      |          |         | Process |         |         |
 |        |      |          |         |Else PV  |         |         |
 +------------------------------------------------------------------+
 |Rcv mgmt|      |          |If FE<   |If FE<   |If FE<   |If FE<   |
 |        |      |          | 2.0 PV  | 2.0 PV  | 2.0 PV  | 2.0 PV  |
 |        |      |          |Else     |Else     |Else     |Else     |
 |        |      |          | Process | Process | Process | Process |
 +------------------------------------------------------------------+
 |Rcv xsrv|      |          |If FE<   |If FE<   |If FE<   |If FE<   |
 |        |      |          | 2.0 PV  | 2.0 PV  | 2.0 PV  | 2.0 PV  |
 |        |      |          |Else     |Else     |Else     |Else     |
 |        |      |          | Process | Process | Process | Process |
 +------------------------------------------------------------------+
 |Rcv spcl|      |          |If FE<   |If FE<   |If FE<   |If FE<   |
 |        |      |          | 2.0 PV  | 2.0 PV  | 2.0 PV  | 2.0 PV  |
 |        |      |          |Else     |Else     |Else     |Else     |
 |        |      |          | Process | Process | Process | Process |
 +------------------------------------------------------------------+
 |Connect.|      | Start T1 |         |         |         |         |
 |Estab.  |      | Start T2 |         |         |         |         |
 |        |      | Start T4 |         |         |         |         |
 |        |      |(if non-0)|         |         |         |         |
 |        |      |if sock_  |         |         |         |         |
 |        |      |  allowed |         |         |         |         |
 |        |      |  = TRUE  |         |         |         |         |
 |        |      | send allo|         |         |         |         |
 |        |      | send test|         |         |         |         |
 |        |      | NEA-FEP  |         |         |         |         |
 |        |      |else      |         |         |         |         |
 |        |      | send proh|         |         |         |         |
 |        |      | send test|         |         |         |         |
 |        |      | NEP-FEP  |         |         |         |         |
 +------------------------------------------------------------------+
 |Connect.|      |          |   PV    |   PV    |   PV    |   PV    |
 |Lost    |      |          |         |         |         |         |
 +------------------------------------------------------------------+
 |Protocol|      |          |Stop all |Stop all |Stop all |Stop all |
 |Violat. |      |          | timers  | timers  | timers  | timers  |
 |        |      |          |Close the|Close the|Close the|Close the|
 |        |      |          | socket  | socket  | socket  | socket  |
 |        |      |          |Connect- |Connect- |Connect- |Connect- |
 |        |      |          |  ing    |  ing    |  ing    |  ing    |
 +------------------------------------------------------------------+

Sprague, et al. Informational [Page 100] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

 |Mgmt.   |Open  |          |         |         |         |         |
 |Open    |socket|          |         |         |         |         |
 |Socket  |Conne-|          |         |         |         |         |
 |        | cting|          |         |         |         |         |
 +------------------------------------------------------------------+
 |Mgmt.   |      |Close the |Stop all |Stop all |Stop all |Stop all |
 |Close   |      | socket   | timers  | timers  | timers  | timers  |
 |Socket  |      |OOS       |Close the|Close the|Close the|Close the|
 |        |      |          | socket  | socket  | socket  | socket  |
 |        |      |          |OOS      |OOS      |OOS      |OOS      |
 +------------------------------------------------------------------+
 |Mgmt.   |sock_ |sock_allo-|sock_all-|sock_all-|sock_all-|sock_all-|
 |Prohibit|allow-| wed=FALSE| owed=   | owed=   | owed=   | owed=   |
 |Socket  |ed =  |          | FALSE   | FALSE   | FALSE   | FALSE   |
 |        |FALSE |          |         |         |send proh|send proh|
 |        |      |          |         |         |start t3 |start t3 |
 |        |      |          |         |         | NEP-FEP | NEP-FEA |
 |        |      |          |         |         |         |         |
 +------------------------------------------------------------------+
 |Mgmt.   |sock_ |sock_allo-|sock_all-|sock_all-|sock_all-|sock_all-|
 |Allow   |allow-| wed=TRUE | owed=   | owed=   | owed=   | owed=   |
 |Traffic |ed =  |          | TRUE    | FALSE   | TRUE    | TRUE    |
 |        |TRUE  |          |send allo|send allo|         |         |
 |        |      |          | NEA-FEP | NEA-FEA |         |         |
 +------------------------------------------------------------------+
 |User    |reject| reject   | reject  | reject  | reject  | send    |
 |Part    |data  | data     | data    | data    | data    | data    |
 |Msgs.   |      |          |         |         |         |         |
 +------------------------------------------------------------------+
 |Request |      |          |If FE<2.0|If FE<2.0|If FE<2.0|If FE<2.0|
 |to Tx   |      |          | Ignore  | Ignore  | Ignore  | Ignore  |
 |mgmt    |      |          |Else     |Else     |Else     |Else     |
 |        |      |          | Process | Process | Process | Process |
 +------------------------------------------------------------------+
 |Request |      |          |If FE<2.0|If FE<2.0|If FE<2.0|If FE<2.0|
 |to Tx   |      |          | Ignore  | Ignore  | Ignore  | Ignore  |
 |xsrv    |      |          |Else     |Else     |Else     |Else     |
 |        |      |          | Process | Process | Process | Process |
 +------------------------------------------------------------------+
 |Request |      |          |If FE<2.0|If FE<2.0|If FE<2.0|If FE<2.0|
 |to Tx   |      |          | Ignore  | Ignore  | Ignore  | Ignore  |
 |spcl    |      |          |Else     |Else     |Else     |Else     |
 |        |      |          | Process | Process | Process | Process |
 +------------------------------------------------------------------+
                 Table 29: TALI 2.0 State Machine

Sprague, et al. Informational [Page 101] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

4.10 TALI 2.0 Specification Limitations

 Several limitations with the TALI 2.0 specification are identified.
 These are considered possible areas for expansion of the protocol in
 the future:
  • Support for different types of routing keys is limited. It is

envisioned that new routing key types will need to be added and

    supported as new applications are identified.
  • An opcode, or new primitive within an existing opcode, could be

added as a means of returning unknown or unsupported data to the

    sender.  In addition to discarding and storing internal debug
    data, an implementation may want to return the original TALI
    message to the sender when the receiver of the message deems the
    message to be unknown, unsupported, or incorrectly formatted.

5. Success/Failure Codes

 The following list provides all the known success/failure codes that
 are being used for the rkrp feature.  New defines will be added to
 the end of the list as they are identified.
 Error #    Meaning
 1          Transaction successfully completed.
 2          Length of TALI msg is insufficient to contain all
            required information for rkrp operation
 3          Unsupported 'rkrp' operation
 4          Invalid SI.  SI must be in range 0..15
 5          Invalid SI/operation combination.  Split and resize only
            supported for SI=4,5,13.  Enter, delete and override
            supported for all SI.
 6          Invalid DPC.  Point code cannot be zero, and must be full
            point code.
 7          Invalid SSN.  SSN must be in range 0..255.
 8          Invalid OPC.  Point code cannot be zero, and must be full
            point code.
 9          Invalid CICS.  Must be in range appropriate for SI and PC
            type.
 10         Invalid CICE.  Must be in range appropriate for SI and PC
            type.
 11         Invalid CIC range.  CICS must be less than or equal to
            CICE.  On a split operation, CICS must be strictly less
            than than CICE (cannot split an range with only one
            entry).
 12         Invalid NCICS.  Must be in range appropriate for SI and
            PC type.

Sprague, et al. Informational [Page 102] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

 13         Invalid NCICE.  Must be in range appropriate for SI and
            PC type.
 14         Invalid new CIC range.  NCICS must be less than or equal
            to NCICE.
 15         Invalid SPLIT value.   Must be in range appropriate for
            SI and PC type.  Must be greater than CICS and less than
            or equal to CICE.
 16         No free entries in table.
 17         CIC range overlaps but does not match existing entry.
 18         Entry already has 16 associations.
 19         Entry to be changed not found in table.
 20         New entry would overlap another entry (allowed to overlap
            the entry being changed, but no others).
 21         Entry to be deleted not found in table.
 22         TUP routing keys are not supported for ANSI networks

6. Security Considerations

 TALI is an interface for the transport of SS7 traffic and management
 messages across an IP network.  As with traditional PSTN networks,
 the IP networks using TALI are expected to well engineered systems.
 The use of virtual private networks and firewalls is to be expected.
 In addition, the use of IPSEC will bring added security benefit to
 the network.

7. References

 [1]  Bell Communications Research, Specification of Signaling System
      Number 7, GT-246-CORE, Bellcore, Issue 1, December 1994.
 [2]  Postel, J., "Internet Protocol", STD 5, RFC 791, September 1981.
 [3]  Postel, J., "Internet Control Message Protocol", STD 5, RFC 792,
      September 1981.
 [4]  Postel, J., "Transmission Control Protocol", STD 7, RFC 793,
      September 1981.
 [5]  Logical Link Control, IEEE 802.2 and ISO 8802.2
 [6]  Carrier Sense Multiple Access with Collision Detection
      (Ethernet), IEEE 802.3 and ISO 8802-3 CSMA/CD.
 [7]  Virtual LAN, IEEE 802.1 Q and ISO 8802-1Q CSMA/CD.
 [8]  Bell Communications Research, Generic Requirements for CCS Nodes
      Supporting ATM High-Speed Signaling Links (HSLs), GR-2878-CORE,
      Issue 1, Bellcore, November 1995.

Sprague, et al. Informational [Page 103] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

 [9]  Bell Communications Research, Asynchronous Transfer Mode (ATM)
      and ATM Adaptation Layer (AAL) Protocols, GR-1113-CORE,
      Bellcore.
 [10] American National Standards Institute, B-ISDN Signaling ATM
      Adaptation Layer - Service Specific Connection Oriented Protocol
      (SSCOP), T1.637.
 [11] American National Standards Institute, B-ISDN Signaling ATM
      Adaptation Layer - Service Specific Coordination Function for
      Support of Signaling at the Network Node Interface (SSCF at the
      NNI), T1.645.
 [12] American National Standards Institute, B-ISDN Signaling ATM
      Adaptation Layer - Layer Management for the SAAL at the NNI,
      T1.652.

8. Acknowledgments

 The authors would like to thank Ken Morneault for his comments and
 contributions to the document.

Sprague, et al. Informational [Page 104] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

9. Authors' Addresses

 David Sprague
 Tekelec
 5200 Paramount Pkwy.
 Morrisville, NC  27560
 Phone: +1 919-460-5563
 EMail: david.sprague@tekelec.com
 Dan Brendes
 Tekelec
 5200 Paramount Pkwy.
 Morrisville, NC  27560
 Phone: +1 919-460-2162
 EMail: dan.brendes@tekelec.com
 Robby Benedyk
 Tekelec
 5200 Paramount Pkwy.
 Morrisville, NC  27560
 Phone: +1 919-460-5533
 EMail: robby.benedyk@tekelec.com
 Joe Keller
 Tekelec
 5200 Paramount Pkwy.
 Morrisville, NC  27560
 Phone: +1 919-460-5549
 EMail: joe.keller@tekelec.com

Sprague, et al. Informational [Page 105] RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001

Full Copyright Statement

 Copyright (C) The Internet Society (2001).  All Rights Reserved.
 This document and translations of it may be copied and furnished to
 others, and derivative works that comment on or otherwise explain it
 or assist in its implementation may be prepared, copied, published
 and distributed, in whole or in part, without restriction of any
 kind, provided that the above copyright notice and this paragraph are
 included on all such copies and derivative works.  However, this
 document itself may not be modified in any way, such as by removing
 the copyright notice or references to the Internet Society or other
 Internet organizations, except as needed for the purpose of
 developing Internet standards in which case the procedures for
 copyrights defined in the Internet Standards process must be
 followed, or as required to translate it into languages other than
 English.
 The limited permissions granted above are perpetual and will not be
 revoked by the Internet Society or its successors or assigns.
 This document and the information contained herein is provided on an
 "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
 TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
 BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
 HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
 MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.

Acknowledgement

 Funding for the RFC Editor function is currently provided by the
 Internet Society.

Sprague, et al. Informational [Page 106]

/data/webs/external/dokuwiki/data/pages/rfc/rfc3094.txt · Last modified: 2001/04/19 18:20 by 127.0.0.1

Donate Powered by PHP Valid HTML5 Valid CSS Driven by DokuWiki