GENWiki

Premier IT Outsourcing and Support Services within the UK

User Tools

Site Tools


rfc:rfc2761

Network Working Group J. Dunn Request for Comments: 2761 C. Martin Category: Informational ANC, Inc.

                                                        February 2000
                  Terminology for ATM Benchmarking

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 (2000).  All Rights Reserved.

Abstract

 This memo discusses and defines terms associated with performance
 benchmarking tests and the results of these tests in the context of
 Asynchronous Transfer Mode (ATM) based switching devices. The terms
 defined in this memo will be used in addition to terms defined in
 RFCs 1242, 2285, and 2544. This memo is a product of the Benchmarking
 Methodology Working Group (BMWG) of the Internet Engineering Task
 Force (IETF).

Introduction

 This document provides terminology for benchmarking ATM based
 switching devices. It extends terminology already defined for
 benchmarking network interconnect devices in RFCs 1242, 2285, and
 2544. Although some of the definitions in this memo may be applicable
 to a broader group of network interconnect devices, the primary focus
 of the terminology in this memo is on ATM cell relay and signaling.
 This memo contains two major sections: Background and Definitions.
 Within the definitions section is a formal definitions subsection,
 provided as a courtesy to the reader, and a measurement definitions
 sub-section, that contains performance metrics with inherent units.
 The divisions of the measurement sub-section follow the BISDN model.

Dunn & Martin Informational [Page 1] RFC 2761 Terminology for ATM Benchmarking February 2000

 The BISDN model comprises four layers and two planes. This document
 addresses the interactions between these layers and how they effect
 IP and TCP throughput. A schematic of the B-ISDN model follows:
  1. ——–|————————–|——————————-

| User Plane | Control Plane

  1. ——–|————————–|——————————–

Services | IP | ILMI | UNI, PNNI

  1. ——–|————————–|———-|———————

AAL | AAL1, AAL2, AAL3/4, AAL5 | AAL5 | SAAL

  1. ——–|————————–|———-|———————

ATM | Cell Relay | OAM, RM

  1. ——–|————————–|——————————–

| Convergence |

 Physical |--------------------------|--------------------------------
          |         Media            |
 ---------|--------------------------|--------------------------------
 This document assumes that necessary services are available and
 active.  For example, IP connectivity requires SSCOP connectivity
 between signaling entities.  Further, it is assumed that the SUT has
 the ability to configure ATM addresses (via hard coded addresses,
 ILMI or PNNI neighbor discovery), has the ability to run SSCOP, and
 has the ability to perform signaled call setups (via UNI or PNNI
 signaling).  This document covers only CBR, VBR and UBR traffic
 types.  ABR will be handled in a separate document.  Finally, this
 document presents only the terminology associated with benchmarking
 IP performance over ATM; therefore, it does not represent a total
 compilation of ATM test terminology.
 The BMWG produces two major classes of documents: Benchmarking
 Terminology documents and Benchmarking Methodology documents. The
 Terminology documents present the benchmarks and other related terms.
 The Methodology documents define the procedures required to collect
 the benchmarks cited in the corresponding Terminology documents.

Existing Definitions

 RFC 1242, "Benchmarking Terminology for Network Interconnect Devices"
 should be consulted before attempting to make use of this document.
 RFC 2544, "Benchmarking Methodology for Network Interconnect Devices"
 contains discussions of a number of terms relevant to the
 benchmarking of switching devices and should be consulted.  RFC 2285,
 "Benchmarking Terminology for LAN Switching Devices" contains a
 number of terms pertaining to traffic distributions and datagram
 interarrival.  For the sake of clarity and continuity, this RFC
 adopts the template for definitions set out in Section 2 of RFC 1242.
 Definitions are indexed and grouped together in sections for ease of

Dunn & Martin Informational [Page 2] RFC 2761 Terminology for ATM Benchmarking February 2000

 reference.  The key words "MUST", "MUST NOT", "REQUIRED", "SHALL",
 "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and
 "OPTIONAL" go in this document are to be interpreted as described in
 RFC 2119.

Definitions

 The definitions presented in this section have been divided into two
 groups.  The first group is formal definitions, which are required in
 the definitions of the performance metrics but are not themselves
 strictly metrics.  These definitions are subsumed from other work
 done in other working groups both inside and outside the IETF.  They
 are provided as a courtesy to the reader.

1. Formal Definitions

1.1. Definition Format (from RFC 1242)

 Term to be defined.
 Definition: The specific definition for the term.
 Discussion: A brief discussion of the term, its application and any
 restrictions on measurement procedures.  These discussions pertain
 solely to the impact of a particular ATM parameter on IP or TCP;
 therefore, definitions which contain no configurable components or
 whose components will have the discussion: None.
 Specification: The working group and document in which the terms are
 specified and are listed in the references section.

1.2. Related Definitions

1.2.1. ATM Adaptation Layer (AAL)

 Definition: The layer in the B-ISDN reference model (see B-ISDN)
 which adapts higher layer PDUs into the ATM layer.
 Discussion: There are four types of adaptation layers: AAL 1: used
 for circuit qemulation, voice over ATM AAL2: used for sub-rated voice
 over ATM AAL3/4: used for data over noisy ATM lines AAL5: used for
 data over ATM, most widely used AAL type

Dunn & Martin Informational [Page 3] RFC 2761 Terminology for ATM Benchmarking February 2000

 These AAL types are not measurements, but it is possible to measure
 the time required for Segmentation and Reassembly (SAR).
 Specification: I.363

1.2.2. ATM Adaptation Layer Type 5 (AAL5)

 Definition: AAL5 adapts multi-cell higher layer PDUs into ATM with
 minimal error checking and no error detection.  The AAL5 CPCS (Common
 Paer Convergence Sub-layer) PDU is defined as follows:
——————————————————————–
Higher Layer PDU Padding (If needed) Trailer
——————————————————————–
 Where the padding is used to ensure that the trailer occupies the
 final 8 octets of the last cell.
 The trailer is defined as follows:
 |--------------|--------------|--------------|--------------|
 |   CPCS-UU    |     CPI      |    Length    |   CRC-32     |
 |--------------|--------------|--------------|--------------|
 where:
 CPCS-UU is the 1 octet Common Part Convergence Sub-layer User to User
 Indication and may be used to communicate between two AAL5 entities.
 CPI is the 1 octet Common Part Indicator and must be set to 0.
 Length is the 2 octet length of the higher layer PDU.
 CRC-32 is a 32 bit (4 octet) cyclic redundancy check over the entire
 PDU.
 Discussion: AAL5 is the adaptation layer for UNI signaling, ILMI,
 PNNI signaling, and for IP PDUs. It is the most widely used AAL type
 to date.  AAL5 requires two distinct processes.  The first is the
 encapsulation, on the transmit side, and de-encapsulation, on the
 receive side, of the higher layer PDU into the AAL5 CPCS PDU which
 requires the computation of the length and the CRC-32.  The time
 required for this process depends on whether the CRC-32 computation
 is done on the interface (on-board) or in machine central memory (in
 core).  On-board computation should produce only a small, constant
 delay; however, in core computation will produce variable delay,
 which will negatively effect TCP RTT computations. The second process
 is segmentation and re-assembly (SAR) which is defined below (see

Dunn & Martin Informational [Page 4] RFC 2761 Terminology for ATM Benchmarking February 2000

 SAR).
 Specification: I.363.5

1.2.3. Asynchronous Transfer Mode (ATM)

 Definition: A transfer mode in which the information is organized
 into 53 octet PDUs called cells. It is asynchronous in the sense that
 the recurrence of cells containing information from an individual
 user is not necessarily periodic.
 Discussion: ATM is based on the ISDN model; however, unlike ISDN, ATM
 uses fixed length (53 octet) cells. Because of the fixed length of
 ATM PDUs, higher layer PDUs must be adapted into ATM using one of the
 four ATM adaptation layers (see AAL).
 Specification: AF-UNI3.1

1.2.4. ATM Link

 Definition: A virtual path link (VPL) or a virtual channel link
 (VCL).
 Discussion: none.
 Specification: AF-UNI3.1

1.2.5. ATM Peer-to-Peer Connection

 Definition: A virtual channel connection (VCC) or a virtual path
 connection (VPC).
 Discussion: none.
 Specification: AF-UNI3.1

1.2.6. ATM Traffic Descriptor

 Definition: A generic list of traffic parameters, which specify the
 intrinsic traffic characteristics of a requested ATM connection (see
 GCRA), which must include PCR and QoS and may include BT, SCR and
 best effort (UBR) indicator.

Dunn & Martin Informational [Page 5] RFC 2761 Terminology for ATM Benchmarking February 2000

 Discussion: The effects of each traffic parameter will be discussed
 individually.
 Specification: AF-UNI3.1

1.2.7. ATM User-User Connection

 Definition: An association established by the ATM Layer to support
 communication between two or more ATM service users (i.e., between
 two or more next higher entities or between two or more ATM-
 entities).  The communications over an ATM Layer connection may be
 either bi-directional or unidirectional. The same Virtual Channel
 Identifier (VCI) is issued for both directions of a connection at an
 interface.
 Discussion: Because ATM is connection oriented, certain features of
 IP (i.e. those which require multicast) are not available.
 Specification: AF-UNI3.1

1.2.8. Broadband ISDN (B-ISDN) Model

 Definition: A layered service model that specifies the mapping of
 higher layer protocols onto ATM and its underlying physical layer.
 The model is composed of four layers: Physical, ATM, AAL and Service.
 Discussion: See discussion above.
 Specification: I.321

1.2.9. Burst Tolerance (BT)

 Definition: A traffic parameter, which, along with the Sustainable
 Cell Rate (SCR), specifies the maximum number of cells which will be
 accepted at the Peak Cell Rate (PCR) on an ATM connection.
 Discussion: BT applies to ATM connections supporting VBR services and
 is the limit parameter of the GCRA. BT will effect TCP and IP PDU
 loss in that cells presented to an interface which violate the BT may
 be dropped, which will cause AAL5 PDU corruption. BT will also effect
 TCP RTT calculation.  BT=(MBS-1)*(1/SCR 1/PCR) (see MBS, PCR, SCR).
 Specification: AF-TM4.0

Dunn & Martin Informational [Page 6] RFC 2761 Terminology for ATM Benchmarking February 2000

1.2.10. Call

 Definition: A call is an association between two or more users or
 between a user and a network entity that is established by the use of
 network capabilities. This association may have zero or more
 connections.
 Discussion: none.
 Specification: AF-UNI3.1

1.2.11. Cell

 Definition: A unit of transmission in ATM. A fixed-size frame
 consisting of a 5-octet header and a 48-octet payload.
 Discussion: none.
 Specification: AF-UNI3.1

1.2.12. Call-based

 Definition: A transport requiring call setups - see CALL definition.
 Discussion: none.
 Specification: AF-UNI3.1

1.2.13. Cell Delay Variation Tolerance (CDVT)

 Definition: ATM layer functions may alter the traffic characteristics
 of ATM connections by introducing Cell Delay Variation. When cells
 from two or more ATM connections are multiplexed, cells of a given
 ATM connection may be delayed while cells of another ATM connection
 are being inserted at the output of the multiplexer.  Similarly, some
 cells may be delayed while physical layer overhead or OAM cells are
 inserted.  Consequently, some randomness may affect the inter-arrival
 time between consecutive cells of a connection as monitored at the
 UNI.  The upper bound on the "clumping" measure is the CDVT.
 Discussion: CDVT effects TCP round trip time calculations.  Large
 values of CDVT will adversely effect TCP throughput and cause SAR
 timeout.  See discussion under SAR.
 Specification: AF-TM4.0

Dunn & Martin Informational [Page 7] RFC 2761 Terminology for ATM Benchmarking February 2000

1.2.14. Cell Header

 Definition: ATM Layer protocol control information.
 Discussion: The ATM cell header is a 5-byte header that contains the
 following fields: Generic Flow Control (GFC) 4 bits Virtual Path
 Identifier (VPI) 8 bits Virtual Channel Identifier (VCI) 16 bits
 Payload Type (PT) 3 bits Cell Loss Priority (CLP) 1 bit Header Error
 Check (HEC) 8 bit CRC computed over the previous four octets
 Each field is discussed in this document.
 Specification: AF-UNI3.1

1.2.15. Cell Loss Priority (CLP)

 Definition: This bit in the ATM cell header indicates two levels of
 priority for ATM cells. CLP=0 cells are higher priority than CLP=1
 cells.  CLP=1 cells may be discarded during periods of congestion to
 preserve the CLR of CLP=0 cells.
 Discussion: The CLP bit is used to determine GCRA contract
 compliance.  Specifically, two traffic contracts may apply to a
 single connection:  CLP=0, meaning only cells with CLP=0, and
 CLP=0+1, meaning cells with CLP=0 or CLP=1.
 Specification: AF-UNI3.1

1.2.16. Connection

 Definition: An ATM connection consists of concatenation of ATM Layer
 links in order to provide an end-to-end information transfer
 capability to access points.
 Discussion: none.
 Specification: AF-UNI3.1

1.2.17. Connection Admission Control (CAC)

 Definition: Connection Admission Control is defined as the set of
 actions taken by the network during the call set-up phase (or during
 call re-negotiation phase) in order to determine whether a connection
 request can be accepted or should be rejected (or whether a request
 for re-allocation can be accommodated).

Dunn & Martin Informational [Page 8] RFC 2761 Terminology for ATM Benchmarking February 2000

 Discussion: CAC is based on the ATM traffic descriptor (see ATM
 traffic descriptor) associated with the call as well as the presented
 and existing load.  It may also be based on administrative policies
 such as calling party number required or access limitations. The
 effect on performance of these policies is beyond the scope of this
 document and will be handled in the BMWG document: Benchmarking
 Terminology for Firewall Performance.
 Specification: AF-UNI3.1

1.2.18. Constant Bit Rate (CBR)

 Definition: An ATM service category which supports a constant and
 guaranteed rate to transport services such as video or voice as well
 as circuit emulation which requires rigorous timing control and
 performance parameters.  CBR requires the specification of PCR and
 QoS (see PCR and QoS).
 Discussion: Because CBR provides minimal cell delay variation (see
 CDV), it should improve TCP throughput by stabilizing the RTT
 calculation.  Further, as CBR generally provides a high priority
 service, meaning that cells with a CBR traffic contract usually take
 priority over other cells during congestion, TCP segment and IP
 packet loss should be minimized.  The cost associated with using CBR
 is the loss of statistical multiplexing.  Since CBR guarantees both
 throughput and CDV control, the connections must be subscribed at
 PCR.  This is extremely wasteful as most protocols, e.g., TCP, only
 utilize full bandwidth on one half of a bi-directional connection.
 Specification: AF-UNI3.1

1.2.19. Cyclic Redundancy Check (CRC)

 Definition: A mathematical algorithm that computes a numerical value
 based on the bits in a block of data. This number is transmitted with
 the data, the receiver uses this information and the same algorithm
 to insure the accurate delivery of data by comparing the results of
 algorithm, and the number received.  If a mismatch occurs, an error
 in transmission is presumed.
 Discussion: CRC is not a measurement, but it is possible to measure
 the amount of time to perform a CRC on a string of bits. This
 measurement will not be addressed in this document. See discussion
 under AAL5.
 Specification: AF-UNI3.1

Dunn & Martin Informational [Page 9] RFC 2761 Terminology for ATM Benchmarking February 2000

1.2.20. End System (ES)

 Definition: A system where an ATM connection is terminated or
 initiated.  An originating end system initiates the ATM connection,
 and terminating end system terminates the ATM connection.  OAM cells
 may be generated and received.
 Discussion: An ES can be the user side of a UNI signaling interface.
 Specification: AF-TEST-0022

1.2.21. Explicit Forward Congestion Indication (EFCI)

 Definition: EFCI is an indication in the PTI field of the ATM cell
 header.  A network element in an impending-congested state or a
 congested state may set EFCI so that this indication may be examined
 by the destination end-system. For example, the end-system may use
 this indication to implement a protocol that adaptively lowers the
 cell rate of the connection during congestion or impending
 congestion.  A network element that is not in a congestion state or
 an impending congestion state will not modify the value of this
 indication.  Impending congestion is the state when network equipment
 is operating around its engineered capacity level.
 Discussion: EFCI may be used to prevent congestion by alerting a
 positive acknowledgement protocol and causing action to be taken.  In
 the case of TCP, when EFCI cells are received the driver software
 could alert the TCP software of impending congestion.  The TCP
 receiver would then acknowledge the current segment and set the
 window size to some very small number.
 Specification: AF-TM4.0

1.2.22. Generic Cell Rate Algorithm (GCRA)

 Definition: The GCRA is used to define conformance with respect to
 the traffic contract of the connection.  For each cell arrival, the
 GCRA determines whether the cell conforms to the traffic contract.
 The UPC function may implement the GCRA, or one or more equivalent
 algorithms to enforce conformance. The GCRA is defined with two
 parameters: the Increment (I) and the Limit (L).
 Discussion: The GCRA increment and limit parameters are mapped to CBR
 and VBR in the following fashion.  For CBR, I=1/PCR and L=CDVT (CDV
 tolerance).  For VBR, there are two GCRA algorithms running (dual
 leaky bucket).  The first functions in the same fashion .bp as CBR,
 I=1/PCR and L=CDVT.  The second, which polices cells which are in
 conformance with the first GCRA uses I=1/SCR and L=BT (see BT, CDV,

Dunn & Martin Informational [Page 10] RFC 2761 Terminology for ATM Benchmarking February 2000

 MBS, PCR and SCR).
 Specification: AF-TM4.0

1.2.23. Generic Flow Control (GFC)

 Definition: GFC is a field in the ATM header, which can be used to
 provide local functions (e.g., flow control). It has local
 significance only and the value encoded in the field is not carried
 end-to-end.
 Discussion: none.
 Specification: AF-UNI3.1

1.2.24. Guaranteed Frame Rate (GFR)

 Definition: The GFR service provides the user with a Minimum Cell
 Rate (MCR) guarantee under the assumption of a given maximum frame
 size (MFS) and a given Maximum Burst Size (MBS).  The MFS and MBS are
 both expressed in units of cells.  GFR only applies to virtual
 channel connections (VCCs).
 Discussion: GFR is intended for users who are either not able to
 specify the range of traffic parameters needed to request most ATM
 services, or are not equipped to comply with the (source) behavior
 rules required by existing ATM services.  Specifically, GFR provides
 the user with the following minimum service guarantee: When the
 network is congested, all frames whose length is less than MFS and
 presented to the ATM interface in bursts less than MBS and at a rate
 less than PCR will be handled with minimum frame loss.  When the
 network is not congested, the user can burst at higher rates.
 The effect of GFR on performance is somewhat problematic as the
 policing algorithm associated with GFR depends on the network load;
 however, under congested condition and assuming a user who is
 following the GFR service agreement, it should improve performance.
 Specification: AF-TM4.1

Dunn & Martin Informational [Page 11] RFC 2761 Terminology for ATM Benchmarking February 2000

1.2.25. Header Error Control (HEC)

 Definition: A check character calculated using an 8 bit CRC computed
 over the first 4 octets of the ATM cell header. This allows for
 single bit error correction or multiple bit error detection.
 Discussion: none.
 Specification: AF-UNI3.1

1.2.26. Integrated Local Management Interface

 Definition: A management protocol which uses SNMPv1 carried on AAL5
 to provide ATM network devices with status and configuration
 information concerning VPCs, VCCs, registered ATM addresses and the
 capabilities of ATM interfaces.
 Discussion: ILMI is a conditionally required portion of UNI3.1;
 however, ILMI 4.0 has been issued as a separate specification.  This
 document will refer to ILMI 4.0.
 Specification: AF-ILMI4.0

1.2.27. Intermediate System (IS)

 Definition: A system that provides forwarding functions or relaying
 functions or both for a specific ATM connection. OAM cells may be
 generated and received.
 Discussion: An IS can be either the user or network side of a UNI
 signaling interface, or the network side of a PNNI signaling
 interface.
 Specification: AF-TEST-0022

1.2.28. Leaky Bucket (LB)

 Definition: Leaky Bucket is the term used as an analogous description
 of the algorithm used for conformance checking of cell flows from a
 user or network. See GCRA and UPC.  The "leaking hole in the bucket"
 applies to the sustained rate at which cells can be accommodated,
 while the "bucket depth" applies to the tolerance to cell bursting
 over a given time period.
 Discussion: There are two types of LB algorithms - single and dual.
 Single LB is used in CBR; dual LB is used in VBR (see CBR and VBR).
 Specification: AF-TM4.0

Dunn & Martin Informational [Page 12] RFC 2761 Terminology for ATM Benchmarking February 2000

1.2.29. Maximum Burst Size (MBS)

 Definition: In the signaling message, the Burst Tolerance (BT) is
 conveyed through the MBS that is coded as a number of cells. The BT
 together with the SCR and the PCR determine the MBS that may be
 transmitted at the peak rate and still is in conformance with the
 GCRA.
 Discussion: See the discussion under BT.
 Specification: AF-TM4.0

1.2.30. Maximum Frame Size (MFS)

 Definition: The MFS is the maximum length of a frame, expressed in
 units of cells, which in interface implementing GFR will accept
 during congested conditions (see GFR).
 Discussion: During congestion, frames whose size is in excess of the
 MFS may be dropped or tagged.  Assuming that the user is adhering to
 the MFS limit, this behavior should improve performance by improving
 congestion.
 Specification: AF-TM4.1

1.2.31. Operations, Administration, and Maintenance (OAM)

 Definition: A group of network management functions that provide
 network fault indication, performance information, and data and
 diagnosis functions.
 Discussion: There are four types of ATM OAM flows: segment or end-
 to-end VP termination management (i.e. F4 segment, F4 E2E) and
 segment or end-to-end VC termination management (i.e. F5 segment, F5
 E2E). These OAM cells can be used to identify fault management,
 connection verification, and loop back measurements.
 Specification: AF-UNI3.1

Dunn & Martin Informational [Page 13] RFC 2761 Terminology for ATM Benchmarking February 2000

1.2.32. Payload Type Indicator (PTI)

 Definition: Payload Type Indicator is the Payload Type field value
 distinguishing the various management cells and user cells as well as
 conveying explicit forward congestion indication (see EFCI).
 Example:  Resource Management cell is indicated as PTI=110, End-to-
 end OAM F5 Flow cell is indicated as PTI=101.
 Discussion: none.
 Specification: AF-UNI3.1

1.2.33. Peak Cell Rate (PCR)

 Definition: A traffic parameter, which specifies the upper bound on
 the rate at which ATM cells can be submitted to an ATM connection.
 This parameter is used by the GCRA.
 Discussion: PCR directly limits the maximum data rate on an ATM
 connection.  If a user violates the PCR, cells may be dropped
 resulting in Cell Loss.  This in turn will negatively impact AAL5
 PDUs, which may be carrying IP datagrams.  See the discussion under
 SAR.
 Specification: AF-TM4.0

1.2.34. Permanent Virtual Circuit (PVC)

 Definition: This is a link with static route(s) defined in advance,
 usually by manual setup.
 Discussion: none.
 Specification: AF-UNI3.1

1.2.35. Permanent Virtual Channel Connection (PVCC)

 Definition: A Virtual Channel Connection (VCC) is an ATM connection
 where switching is performed on the VPI/VCI fields of each cell. A
 permanent VCC is one that is provisioned through some network
 management function and left up indefinitely.
 Discussion: none.
 Specification: AF-UNI3.1

Dunn & Martin Informational [Page 14] RFC 2761 Terminology for ATM Benchmarking February 2000

1.2.36. Permanent Virtual Path Connection: (PVPC)

 Definition: A Virtual Path Connection (VPC) is an ATM connection
 where switching is performed on the VPI field only of each cell. A
 permanent VPC is one that is provisioned through some network
 management function and left up indefinitely.
 Discussion: none.
 Specification: AF-UNI3.1

1.2.37. Private Network-Network Interface (PNNI)

 Definition: A routing information protocol that enables extremely,
 scalable, full function, dynamic multi-vendor ATM switches to be
 integrated in the same network.
 Discussion: PNNI consists of signaling and routing between ATM
 network devices.  PNNI signaling is based on UNI 4.0 signaling
 between two network side interfaces, while PNNI routing provides a
 mechanism to route ATM cells between two separate, autonomous ATM
 networks.
 Specification: AF-PNNI1.0

1.2.38. Protocol Data Unit (PDU)

 Definition: A PDU is a message of a given protocol comprising payload
 and protocol-specific control information, typically contained in a
 header.  PDUs pass over the protocol interfaces that exist between
 the layers of protocols (per OSI model).
 Discussion: In ATM networks, a PDU can refer to an ATM cell, multiple
 ATM cells, an AAL segment, an IP datagram and others.
 Specification: Common Usage

1.2.39. Segmentation and Reassembly (SAR)

 Definition: The process used by the AAL in the B-ISDN reference model
 (see B-ISDN) which fragments higher layer PDUs into ATM cells.
 Discussion: SAR is not a measurement, but the speed in which SAR can
 be completed on a bit stream can be measured. Although this
 measurement is not included in this document, it should be noted that
 the manner in which SAR is performed will greatly effect performance.
 SAR can be performed either on the interface card (on board) or in
 machine central memory (in core).  On-board computation should

Dunn & Martin Informational [Page 15] RFC 2761 Terminology for ATM Benchmarking February 2000

 produce only a small, constant delay; however, in core computation
 will produce variable delay, which will negatively effect TCP RTT
 computations.  This situation is further complicated by the location
 of the CRC-32 calculation.  Given an in core CRC-32 calculation, bus
 contention may cause on board SAR to be slower than in core SAR.
 Clearly, on board CRC-32 calculation and SAR will produce the most
 favorable performance results.
 SAR performance will also be effected by ATM layer impairments.  Cell
 error (CE), cell loss(CL), cell mis-insertion (CM) and cell delay
 variation (CDV) will all negatively effect SAR.  CE will cause an
 AAL5 PDU to fail the CRC-32 check and be discarded, thus discarding
 the packet which the PDU contained.  CL and CM will both cause an
 AAL5 PDU to fail the length check and be discarded.  CL can have
 other effects depending on whether the cell which was lost is the
 final cell (PTI=1) of the AAL5 PDU.  The following discussion
 enumerates the possibilities.
 1. PTI=0 cell is lost.  In this case, re-assembly registers a length
 discrepancy and discards the PDU.
 2. PTI=1 cell is lost.
 2.  A.  The AAL5 re-assembly timer expires before the first cell,
 PTI=0, of the next AAL5 PDU arrives.  The AAL5 PDU with the missing
 PTI=1 cell is discarded due to re-assembly timeout and one packet is
 lost.
 2.  B.  The first cell of the next AAL5 PDU arrives before the re-
 assembly timer expires.  The AAL5 with the missing PTI=1 cell is
 prepended to the next AAL5 PDU in the SAR engine.  This yields two
 possibilities:
 2. B. i. The AAL5 re-assembly timer expires before the last cell,
 PTI=1, of the next AAL5 PDU arrives.  The AAL5 PDU with the missing
 PTI=1 cell and the next AAL5 PDU are discarded due to re-assembly
 timeout and two packets are lost.
 2. B. ii. The last cell of the next AAL5 PDU arrives before the re-
 assembly timer expires.  In this case, AAL5 registers a length
 discrepancy and discards the PDU; therefore, the AAL5 PDU with the
 missing PTI=1 cell and the next AAL5 PDU are discarded due to their
 concatenation and two packets are lost.

Dunn & Martin Informational [Page 16] RFC 2761 Terminology for ATM Benchmarking February 2000

 2. C. Coupled with re-assembly, there exists some mechanism for
 identifying the start of a higher layer PDU, e.g., IP, and the cells
 associated with the first incomplete AAL5 PDU are discarded,
 resulting in the loss of one packet.
 Specification: AF-UNI3.1

1.2.40. Sustainable Cell Rate (SCR)

 Definition: The SCR is an upper bound on the conforming average rate
 of an ATM connection over time scales which are long relative to
 those for which the PCR is defined. Enforcement of this bound by the
 UPC could allow the network to allocate sufficient resources, but
 less than those based on the PCR, and still ensure that the
 performance objectives (e.g., for Cell Loss Ratio) can be achieved.
 Discussion: SCR limits the average data rate on an ATM connection.
 If a user violates the SCR, cells may be dropped resulting in Cell
 Loss.  This in turn will negatively impact AAL5 PDUs, which may be
 carrying IP datagrams.  See the discussion under SAR.
 Specification: AF-TM4.0

1.2.41. Switched Connection

 Definition: A connection established via signaling.
 Discussion: none.
 Specification: AF-UNI3.1

1.2.42. Switched Virtual Channel Connection (SVCC)

 Definition: A Switched VCC is one that is established and taken down
 dynamically through control signaling. A Virtual Channel Connection
 (VCC) is an ATM connection where switching is performed on the
 VPI/VCI fields of each cell.
 Discussion: none.
 Specification: AF-UNI3.1

Dunn & Martin Informational [Page 17] RFC 2761 Terminology for ATM Benchmarking February 2000

1.2.43. Switched Virtual Circuit (SVC)

 Definition: A connection established via signaling. The user defines
 the endpoints when the call is initiated.
 Discussion: SVCs are established using either UNI signaling or PNNI
 signaling.  The signaling state machine implements several timers,
 which can effect the time required for call establishment.  This will
 effect TCP round trip time calculation, effecting TCP throughput.
 Specifically, there are two possibilities.  In the case where Call
 Proceeding is not implemented, there is only one timer, T310, with a
 value of 10 seconds.  In the case where Call Proceeding is
 implemented, there are two timers, T303 and T310, with the values 4
 and 10 seconds, respectively.  In either case, if a timer, either
 T303 or T310, expires after a Setup message is send, the calling
 party has the option of re-transmitting the Setup.  In the T303 case,
 this yields a maximum setup time of 18 seconds and, In the T310 case,
 a maximum setup time of 20 seconds.  Thus, the initial TCP RTT
 calculation will be on he order of 20 seconds.
 Specification: AF-UNI3.1, AF-UNI4.0, AF-PNNI1.0

1.2.44. Switched Virtual Path Connection (SVPC)

 Definition: A Switched Virtual Path Connection is one that is
 established and taken down dynamically through control signaling.  A
 Virtual Path Connection (VPC) is an ATM connection where switching is
 performed on the VPI field only of each cell.
 Discussion: none.
 Specification: AF-UNI3.1

1.2.45. Traffic Contract

 Definition: A specification of the negotiated traffic characteristics
 of an ATM connection.
 Discussion: See discussions under BT, CAC, CDV, GCRA, PCR and SCR.
 Specification: AF-TM4.0

1.2.46. Traffic Management (TM)

 Definition: Traffic Management is the aspect of the traffic control
 and congestion control procedures for ATM. ATM layer traffic control
 refers to the set of actions taken by the network to avoid congestion
 conditions.  ATM layer congestion control refers to the set of

Dunn & Martin Informational [Page 18] RFC 2761 Terminology for ATM Benchmarking February 2000

 actions taken by the network to minimize the intensity, spread and
 duration of congestion. The following functions form a framework for
 managing and controlling traffic and congestion in ATM networks and
 may be used in appropriate combinations.
    Connection Admission Control
    Feedback Control
    Usage Parameter Control
    Priority Control
    Traffic Shaping
    Network Resource Management
    Frame Discard
    ABR Flow Control
 Discussion: See CAC and traffic shaping.
 Specification: AF-TM4.0

1.2.47. Traffic Shaping (TS)

 Definition: Traffic Shaping is a mechanism that alters the traffic
 characteristics of a stream of cells on a connection to achieve
 better network efficiency, while meeting the QoS objectives, or to
 ensure conformance at a subsequent interface. Traffic shaping must
 maintain cell sequence integrity on a connection.  Shaping modifies
 traffic characteristics of a cell flow with the consequence of
 increasing the mean Cell Transfer Delay.
 Discussion: TS should improve TCP throughput by reducing RTT
 variations.  As a result, TCP RTT calculations should be more stable.
 Specification: AF-UNI3.1

1.2.48. Transmission Convergence (TC)

 Definition: A sub-layer of the physical layer of the B-ISDN model
 transforms the flow of cells into a steady flow of bits and bytes for
 transmission over the physical medium. On transmit the TC sublayer
 maps the cells to the frame format, generates the Header Error Check
 (HEC), and sends idle cells when the ATM layer has none. to send. On
 reception, the TC sublayer delineates individual cells in the
 received bit stream, and uses the HEC to detect and correct received
 errors.

Dunn & Martin Informational [Page 19] RFC 2761 Terminology for ATM Benchmarking February 2000

 Discussion: TC is not a measurement, but the speed in which TC can
 occur on a bit stream can be measured. This measurement will not be
 discussed in this document; however, its value should be constant and
 small with respect to cell inter-arrival at the maximum data rate.
 Specification: AF-UNI3.1

1.2.49. Unspecified Bit Rate (UBR)

 Definition: UBR is an ATM service category, which does not specify
 traffic related service guarantees. Specifically, UBR does not
 include the notion of a per-connection-negotiated bandwidth.  No
 commitments are made with respect to the cell loss ratio experienced
 by a UBR connection, or as to the cell transfer delay experienced by
 cells on the connection.
 Discussion: RFC 2331 specifies UBR service class for IP over ATM.
 UBR service models the "best effort" service type specified in RFC
 791; however, UBR has specific drawbacks with respect to TCP service.
 Since UBR makes no guarantee with respect to cell loss (CL), cell
 delay variation (CDV) or cell mis-insertion(CM), TCP RTT estimates
 will be highly variable.  Further, all negatively impact AAL5 re-
 assembly, which in turn may cause packet loss.  See discussions under
 CDV and SAR.
 Specification: AF-TM4.0

1.2.50. Usage Parameter Control (UPC)

 Definition: Usage Parameter Control is defined as the set of actions
 taken by the network to monitor and control traffic, in terms of
 traffic offered and validity of the ATM connection, at the end-system
 access.  Its main purpose is to protect network resources from
 malicious as well as unintentional misbehavior, which can affect the
 QoS of established connections, by detecting violations of negotiated
 parameters and taking appropriate actions.
 Discussion: See discussions under BT, CAC, CDV, GCRA, PCR and SCR.
 Specification: AF-TM4.0

1.2.51. User-Network Interface (UNI)

 Definition: An interface point between ATM end users and a private
 ATM switch, or between a private ATM switch and the public carrier
 ATM network; defined by physical and protocol specifications per ATM
 Forum UNI documents.  The standard adopted by the ATM Forum to define
 connections between users or end stations and a local switch.

Dunn & Martin Informational [Page 20] RFC 2761 Terminology for ATM Benchmarking February 2000

 Discussion: none.
 Specification: AF-UNI3.1

1.2.52. Variable Bit Rate (VBR)

 Definition: An ATM Forum defined service category which supports
 variable bit rate data traffic with average and peak traffic
 parameters.
 Discussion: VBR may potentially adversely effect TCP throughput due
 to large RTT variations.  This in turn will cause the TCP RTT
 estimates to be unstable.
 Specification: AF-TM4.0

1.2.53. Virtual Channel (VC)

 Definition: A communications channel that provides for the sequential
 unidirectional transport of ATM cells.
 Discussion: none.
 Specification: AF-TM3.1

1.2.54. Virtual Channel Connection (VCC)

 Definition: A concatenation of VCIs that extends between the points
 where the ATM service users access the ATM layer. The points at which
 the ATM cell payload is passed to, or received from, the users of the
 ATM Layer (i.e., a higher layer or ATM-entity) for processing signify
 the endpoints of a VCC. VCCs are unidirectional.
 Discussion: none.
 Specification: AF-TM3.1

Dunn & Martin Informational [Page 21] RFC 2761 Terminology for ATM Benchmarking February 2000

1.2.55. Virtual Channel Identifier (VCI)

 Definition: A unique numerical tag as defined by a 16 bit field in
 the ATM cell header that identifies a virtual channel, over which the
 cell is to travel.
 Discussion: none.
 Specification: AF-UNI3.1

1.2.56. Virtual Path (VP)

 Definition: A unidirectional logical association or bundle of VCs.
 Discussion: none.
 Specification: AF-UNI3.1

1.2.57. Virtual Path Connection (VPC)

 Definition: A concatenation of VPIs between Virtual Path Terminators
 (VPTs). VPCs are unidirectional
 Discussion: none.
 Specification: AF-TM3.1

1.2.58. Virtual Path Identifier (VPI)

 Definition: An eight-bit field in the ATM cell header that indicates
 the virtual path over which the cell should be routed.
 Discussion: none.
 Specification: AF-UNI3.1

2. Performance Metrics

2.1. Definition Format (from RFC 1242)

 Metric to be defined.
 Definition: The specific definition for the metric.
 Discussion: A brief discussion of the metric, its application and any
 restrictions on measurement procedures.

Dunn & Martin Informational [Page 22] RFC 2761 Terminology for ATM Benchmarking February 2000

 Measurement units: Intrinsic units used to quantify this metric. This
 includes subsidiary units; e.g., microseconds are acceptable if the
 intrinsic unit is seconds.

2.2. Definitions

2.2.1. Physical Layer - SONET

2.2.1.1. Pointer Movements

 Definition: Pointer Movements is the number of changes in a SONET
 pointer due to clock synchronization slips.
 Discussion: SONET Pointer Movements can cause loss of information in
 the SONET payload envelop (SPE) which contains IP datagrams, either
 in the form of ATM cells or as PPP delimited PDUs.
 Measurement Units: Per second.

2.2.1.2. Transport Overhead Error Count

 Definition: SONET Transport Overhead Error Count is the number of
 SONET transport overhead errors detected.
 Discussion: SONET Transport Overhead Errors SONET Transport Overhead
 Errors cause SONET frames to be lost.  These frames may contain IP
 datagrams; either in the form of cells or as PPP delimited PDUs.
 Measurement Units: Positive integer

2.2.1.3. Path Overhead Error Count

 Definition: SONET Path Overhead Error Count is the number of SONET
 path overhead errors detected.
 Discussion: SONET Path Overhead Errors cause SONET frames to be lost.
 These frames may contain IP datagrams; either in the form of cells or
 as PPP delimited PDUs.
 Measurement Units: Positive integer

Dunn & Martin Informational [Page 23] RFC 2761 Terminology for ATM Benchmarking February 2000

2.2.2. ATM Layer

2.2.2.1. Cell Delay Variation (CDV)

 Definition: The variation in cell transfer delay (CTD) associated
 with a given traffic load, orientation and distribution, as well as
 an integration period. CDV = max (CTD) - min (CTD) where max and min
 indicate the maximum and minimum over the integration period,
 respectively.
 Discussion: CDV is a component of cell transfer delay, induced by
 buffering and cell scheduling. Peak-to-peak CDV is a QoS delay
 parameter associated with CBR and VBR services. The peak-to-peak CDV
 is the ((1-a) quantile of the CTD) minus the fixed CTD that could be
 experienced by any delivered cell on a connection during the entire
 connection holding time.  The parameter "a" is the probability of a
 cell arriving late.
 CDV effects TCP round trip time calculations.  Large values of CDV
 will adversely effect TCP throughput and cause SAR timeout.  See
 discussion under SAR.
 Measurement Units: seconds

2.2.2.2. Cell Error Ratio (CER)

 Definition: The ratio of cells with payload errors in a transmission
 in relation to the total number of cells sent in a transmission
 associated with a given traffic load, orientation and distribution,
 as well as an integration period.  Note that errors occurring in the
 cell header will cause cell loss at the ATM layer.  Note further that
 multiple errors in a payload will only be counted as one cell payload
 error.
      CER = Cells with payload errors / Total Cells Transmitted.
 Discussion: The measurement is taken over a time interval and is
 desirable to be measured on an in-service circuit.  CER is closely
 related to the number of corrupted AAL5 PDUs; however, there is not a
 direct numerical correlation between the number of errored cells and
 the number of corrupted AAL5 PDUs.  There are two cases described
 below.
 1. Only one cell in an AAL5 PDU contains payload errors.  In this
 case, there is a one-to-one correspondence between cell payload
 errors and the number of corrupted AAL5 PDUs.

Dunn & Martin Informational [Page 24] RFC 2761 Terminology for ATM Benchmarking February 2000

 2. Multiple cells in the AAL5 PDU contain payload errors. In this
 case, there is not a one-to-one correspondence between cell payload
 errors and the number of corrupted AAL5 PDUs.
 Measurement Units: dimensionless.

2.2.2.3. Cell Loss Ratio (CLR)

 Definition: The ratio of lost cells in a transmission in relation to
 the total cells sent in a transmission associated with a given
 traffic load, orientation and distribution, as well as an integration
 period.
      CLR = Lost Cells / Total Cells Transmitted.
 Discussion: CLR is a negotiated QoS parameter and acceptable values
 are network specific. The objective is to minimize CLR provided the
 end-system adapts the traffic to the changing ATM layer transfer
 characteristics. The CLR parameter is the value of CLR that the
 network agrees to offer as an objective over the lifetime of the
 connection. It is expressed as an order of magnitude, having a range
 of 10^-1 to 10^-15 and unspecified.
 CLR indicates the number of ATM cells lost in relation to the total
 number of cells sent. CLR is closely related to the number of
 corrupted AAL5 PDUs; however, there is not a direct numerical
 correlation between the number of cells lost and the number of
 corrupted AAL5 PDUs.  See the discussion under SAR.
 Measurement Units: dimensionless.

2.2.2.4. Cell Misinsertion Ratio (CMR)

 Definition: The ratio of cells received at an endpoint that were not
 originally transmitted by the source end in relation to the total
 number of cells properly transmitted associated with a given traffic
 load, orientation and distribution, as well as an integration period.
      CMR = Misinserted Cells / Total Cells Transmitted.
 Discussion: The measurement is taken over a time interval and is
 desirable to be measured on an in-service circuit.  CMR is closely
 related to the number of corrupted AAL5 PDUs; however, there is not a
 direct numerical correlation between the number of mis-inserted cells
 and the number of corrupted AAL5 PDUs.  There are two cases described
 below.

Dunn & Martin Informational [Page 25] RFC 2761 Terminology for ATM Benchmarking February 2000

 1.  Only one cell is mis-inserted into an AAL5 PDU.  In this case,
 there is a one-to-one correspondence between cell mis-insertion and
 the number of corrupted AAL5 PDUs.
 2.  Multiple cells are mis-inserted into an AAL5. In this case, there
 is not a one-to-one correspondence between cell mis-insertion and the
 number of corrupted AAL5 PDUs.
 Measurement Units: dimensionless.

2.2.2.5. Cell Rate Margin (CRM)

 Definition: This is a measure of the difference between the effective
 bandwidth allocation and the allocation for sustainable rate in cells
 per second.
 Discussion: This measures the amount of provisioned bandwidth which
 is not utilized.  This lack of utilization may be caused by
 encapsulation overhead, e.g., AAL5 trailer and padding, or by the
 protocol itself, e.g., TCP usually transmits in only one direction.
 Measurement units: Cells per second

2.2.2.6. CRC Error Ratio

 Definition: The ratio of PDUs received at an endpoint that which
 contain an invalid CRC in relation to the total number of cells
 properly transmitted associated with a given traffic load,
 orientation and distribution, as well as an integration period.
 Discussion: CRC errors cause ATM cells to be lost.  Although this
 will appear as cell loss at the ATM layer, this measurement can be
 made in-service using a test probe which measures CRC errors at the
 TC layer.
 Measurement Units: dimensionless

2.2.2.7. Cell Transfer Delay (CTD)

 Definition: The elapsed time between a cell exit event at the
 measurement point 1 (e.g., at the source UNI) and the corresponding
 cell entry event at a measurement point 2 (e.g., the destination UNI)
 for a particular connection.

Dunn & Martin Informational [Page 26] RFC 2761 Terminology for ATM Benchmarking February 2000

 Discussion: The cell transfer delay between two measurement points is
 the sum of the total inter-ATM node transmission delay and the total
 ATM node processing delay.  While this number is a constant and
 should not adversely effect performance, it is a component in RTT.
 Measurement units: seconds

2.2.3. ATM Adaptation Layer (AAL) Type 5 (AAL5)

2.2.3.1. AAL5 Re-assembly Errors

 Definition: AAL5 Re-assembly Errors constitute any error, which
 causes the AAL5 PDU to be corrupted.
 Discussion: AAL5 Re-assembly errors cause AAL5 PDUs to be lost.
 These PDUs may contain IP datagrams.
 Measurement Units: Positive Integer

2.2.3.2. AAL5 Reassembly Time

 Definition: AAL5 Reassembly Time constitutes the time between the
 arrival of the final cell in the AAL5 PDU and the AAL5 PDUs payload
 being made available to the service layer.
 Discussion: AAL5 Reassembly time directly effects TCP round trip time
 calculations.
 Measurement Units: seconds

2.2.3.3. AAL5 CRC Error Ratio

 Definition: The ratio of PDUs received at an endpoint that which
 contain an invalid CRC in relation to the total number of cells
 properly transmitted associated with a given traffic load,
 orientation and distribution, as well as an integration period.
 Discussion: AAL5 CRC errors cause AAL5 re-assembly errors.  See
 discussion under AAL5 re-assembly errors.
 Measurement Units: dimensionless

Dunn & Martin Informational [Page 27] RFC 2761 Terminology for ATM Benchmarking February 2000

2.2.4. ATM Service: Signaling

2.2.4.1. CAC Denial Time

 Definition: The amount of time required for CAC to determine that a
 call must be rejected.
 Discussion: In the case where Call Proceeding is implemented, this
 number will be less than 4 seconds. Otherwise, it will be less than
 10 seconds.  Large values of this measurement will adversely effect
 performance on systems where an alternate, non-NBMA, service is
 available.
 Measurement Units: seconds

2.2.4.2. Connection Establishment Time

 Definition: The amount of time between the first Setup message from
 the calling party and the Connect message to the calling party.
 Discussion:  See discussion under SVC.
 Measurement Units: seconds

2.2.4.3. Connection Teardown Time

 Definition: The amount of between the Release message being sent and
 the Release Complete message being received.
 Discussion: Large values of this measurement will adversely effect
 performance in systems where the total number of open calls or VCs is
 limited.  Specifically, a new VC cannot be instantiated with the same
 VPI/VCI before the old one is released.
 Measurement Units: seconds

2.2.4.4. Crankback Time

 Definition: The amount of time between the issuance of the first
 release or release complete message by the switch where the current
 Designated Transit List (DTL) is blocked and the receipt of the SETUP
 with the updated DTLs by the target switch.
 Discussion: This measurement does not take into account the amount of
 time associated with either the successful portion of the call setup
 transit or the time required for the calling party to receive .bp a
 response from the called party.  As a result, the call may still fail
 to complete if the call setup timer on the calling party expires.

Dunn & Martin Informational [Page 28] RFC 2761 Terminology for ATM Benchmarking February 2000

 See discussion under SVC.
 Measurement Units: seconds

2.2.4.5. Route Update Response Time

 Definition: The amount of time between the receipt of a PNNI Topology
 State Element (PTSE), which is the PNNI routing PDU, containing a
 topology different from the current topology and the point at which
 the switch begins to generate DTLs reflecting the routing change.
 Discussion: This measurement provides a lower bound on the amount of
 time during which SETUP messages will be forwarded along a sub-
 optimal or blocked path.
 Measurement Units: seconds

2.2.5. ATM Service: ILMI

2.2.5.1. MIB Alignment Time

 Definition: The amount of time between the issuance of the final cold
 start message and the final get response associated with the exchange
 of static MIB information.
 Discussion: This measurement reflects the amount of time required by
 the switch and end system to exchange all information required to
 characterize and align the capabilities of both systems.  It does not
 include address registration.  It should also be noted that this
 measurement will depend on the number of MIB elements implemented by
 both systems.
 Measurement Units: seconds

2.2.5.2. Address Registration Time

 Definition: The amount of time between the initial set request issued
 by the switch and the final get response issued by the switch.
 Discussion: This measurement assumes that the switch has checked the
 network prefix status object and the end system has checked the ATM
 address status object.  In the case where the end system checks the
 ATM address status object only after the switch has issued a set
 request of the network prefix status object, this measurement will
 not reflect the actual time required to complete the address
 registration.
 Measurement Units: seconds

Dunn & Martin Informational [Page 29] RFC 2761 Terminology for ATM Benchmarking February 2000

3. Security Considerations

 As this document is solely for providing terminology and describes
 neither a protocol nor an implementation, there are no security
 considerations associated with this document.

4. Notices

 The IETF takes no position regarding the validity or scope of any
 intellectual property or other rights that might be claimed to
 pertain to the implementation or use of the technology described in
 this document or the extent to which any license under such rights
 might or might not be available; neither does it represent that it
 has made any effort to identify any such rights.  Information on the
 IETFs procedures with respect to rights in standards-track and
 standards-related documentation can be found in BCP-11.  Copies of
 claims of rights made available for publication and any assurances of
 licenses to be made available, or the result of an attempt made to
 obtain a general license or permission for the use of such
 proprietary rights by implementors or users of this specification can
 be obtained from the IETF Secretariat.
 The IETF invites any interested party to bring to its attention any
 copyrights, patents or patent applications, or other proprietary
 rights which may cover technology that may be required to practice
 this standard.  Please address the information to the IETF Executive
 Director.

5. References

 [AF-ILMI4.0]   ATM Forum Integrated Local Management Interface
                Version 4.0, af-ilmi-0065.000, September 1996.
 [AF-TEST-0022] Introduction to ATM Forum Test Specifications, af-
                test-0022.00, December 1994.
 [AF-TM4.0]     ATM Forum, Traffic Management Specification Version
                4.0, af-tm-0056.00, April 1996.
 [AF-TM4.1]     ATM  Forum, Traffic Management Specification Version
                4.1 (final ballot), btd-tm-01.02, July 1998.
 [AF-UNI3.1]    ATM Forum, User Network Interface Specification
                Version 3.1, September 1994.
 [AF-UNI4.0]    ATM Forum, User Network Interface Specification
                Version 4.0, July 1996.

Dunn & Martin Informational [Page 30] RFC 2761 Terminology for ATM Benchmarking February 2000

 [I.321]        ITU-T, B-ISDN protocol reference model and its
                application, April 1991.
 [I.363]        ITU-T, B-ISDN ATM Adaptation Layer Specification
                series, 1996-1997.
 [I.363.5]      ITU-T, B-ISDN ATM Adaptation Layer Specification: Type
                5 AAL, August 1996.

6. Editors' Addresses

 Jeffrey Dunn
 Advanced Network Consultants, Inc.
 4214 Crest Place
 Ellicott City, MD 21043 USA
 Phone: +1 (410) 750-1700
 EMail: Jeffrey.Dunn@worldnet.att.net
 Cynthia Martin
 Advanced Network Consultants, Inc.
 11241-B Skilift Court
 Columbia, MD 21044 USA
 Phone: +1 (410) 730-6300
 EMail: Cynthia.E.Martin@worldnet.att.net

Dunn & Martin Informational [Page 31] RFC 2761 Terminology for ATM Benchmarking February 2000

7. Full Copyright Statement

 Copyright (C) The Internet Society (2000).  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.

Dunn & Martin Informational [Page 32]

/data/webs/external/dokuwiki/data/pages/rfc/rfc2761.txt · Last modified: 2000/02/07 17:21 (external edit)