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rfc:rfc7877

Internet Engineering Task Force (IETF) K. Cartwright Request for Comments: 7877 V. Bhatia Category: Standards Track TNS ISSN: 2070-1721 S. Ali

                                                               NeuStar
                                                           D. Schwartz
                                                              XConnect
                                                           August 2016
           Session Peering Provisioning Framework (SPPF)

Abstract

 This document specifies the data model and the overall structure for
 a framework to provision Session Establishment Data (SED) into
 Session Data Registries and SIP Service Provider (SSP) data stores.
 The framework is called the "Session Peering Provisioning Framework"
 (SPPF).  The provisioned data is typically used by network elements
 for session establishment.

Status of This Memo

 This is an Internet Standards Track document.
 This document is a product of the Internet Engineering Task Force
 (IETF).  It represents the consensus of the IETF community.  It has
 received public review and has been approved for publication by the
 Internet Engineering Steering Group (IESG).  Further information on
 Internet Standards is available in Section 2 of RFC 7841.
 Information about the current status of this document, any errata,
 and how to provide feedback on it may be obtained at
 http://www.rfc-editor.org/info/rfc7877.

Cartwright, et al. Standards Track [Page 1] RFC 7877 SSPF August 2016

Copyright Notice

 Copyright (c) 2016 IETF Trust and the persons identified as the
 document authors.  All rights reserved.
 This document is subject to BCP 78 and the IETF Trust's Legal
 Provisions Relating to IETF Documents
 (http://trustee.ietf.org/license-info) in effect on the date of
 publication of this document.  Please review these documents
 carefully, as they describe your rights and restrictions with respect
 to this document.  Code Components extracted from this document must
 include Simplified BSD License text as described in Section 4.e of
 the Trust Legal Provisions and are provided without warranty as
 described in the Simplified BSD License.

Table of Contents

 1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
 2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   6
 3.  Framework High-Level Design . . . . . . . . . . . . . . . . .   7
   3.1.  Framework Data Model  . . . . . . . . . . . . . . . . . .   7
   3.2.  Time Value  . . . . . . . . . . . . . . . . . . . . . . .  10
   3.3.  Extensibility . . . . . . . . . . . . . . . . . . . . . .  10
 4.  Substrate Protocol Requirements . . . . . . . . . . . . . . .  11
   4.1.  Mandatory Substrate . . . . . . . . . . . . . . . . . . .  11
   4.2.  Connection Oriented . . . . . . . . . . . . . . . . . . .  11
   4.3.  Request and Response Model  . . . . . . . . . . . . . . .  11
   4.4.  Connection Lifetime . . . . . . . . . . . . . . . . . . .  11
   4.5.  Authentication  . . . . . . . . . . . . . . . . . . . . .  12
   4.6.  Authorization . . . . . . . . . . . . . . . . . . . . . .  12
   4.7.  Confidentiality and Integrity . . . . . . . . . . . . . .  12
   4.8.  Near Real Time  . . . . . . . . . . . . . . . . . . . . .  12
   4.9.  Request and Response Sizes  . . . . . . . . . . . . . . .  12
   4.10. Request and Response Correlation  . . . . . . . . . . . .  13
   4.11. Request Acknowledgement . . . . . . . . . . . . . . . . .  13
 5.  Base Framework Data Structures and Response Codes . . . . . .  13
   5.1.  Basic Object Type and Organization Identifiers  . . . . .  13
   5.2.  Various Object Key Types  . . . . . . . . . . . . . . . .  14
     5.2.1.  Generic Object Key Type . . . . . . . . . . . . . . .  14
     5.2.2.  Derived Object Key Types  . . . . . . . . . . . . . .  15
   5.3.  Response Message Types  . . . . . . . . . . . . . . . . .  16
 6.  Framework Data Model Objects  . . . . . . . . . . . . . . . .  18
   6.1.  Destination Group . . . . . . . . . . . . . . . . . . . .  18
   6.2.  Public Identifier . . . . . . . . . . . . . . . . . . . .  19
   6.3.  SED Group . . . . . . . . . . . . . . . . . . . . . . . .  25
   6.4.  SED Record  . . . . . . . . . . . . . . . . . . . . . . .  29
   6.5.  SED Group Offer . . . . . . . . . . . . . . . . . . . . .  33
   6.6.  Egress Route  . . . . . . . . . . . . . . . . . . . . . .  35

Cartwright, et al. Standards Track [Page 2] RFC 7877 SSPF August 2016

 7.  Framework Operations  . . . . . . . . . . . . . . . . . . . .  36
   7.1.  Add Operation . . . . . . . . . . . . . . . . . . . . . .  37
   7.2.  Delete Operation  . . . . . . . . . . . . . . . . . . . .  37
   7.3.  Get Operations  . . . . . . . . . . . . . . . . . . . . .  38
   7.4.  Accept Operations . . . . . . . . . . . . . . . . . . . .  38
   7.5.  Reject Operations . . . . . . . . . . . . . . . . . . . .  39
   7.6.  Get Server Details Operation  . . . . . . . . . . . . . .  39
 8.  XML Considerations  . . . . . . . . . . . . . . . . . . . . .  40
   8.1.  Namespaces  . . . . . . . . . . . . . . . . . . . . . . .  40
   8.2.  Versioning and Character Encoding . . . . . . . . . . . .  40
 9.  Security Considerations . . . . . . . . . . . . . . . . . . .  41
   9.1.  Confidentiality and Authentication  . . . . . . . . . . .  41
   9.2.  Authorization . . . . . . . . . . . . . . . . . . . . . .  41
   9.3.  Denial of Service . . . . . . . . . . . . . . . . . . . .  41
     9.3.1.  DoS Issues Inherited from the Substrate Mechanism . .  42
     9.3.2.  DoS Issues Specific to SPPF . . . . . . . . . . . . .  42
   9.4.  Information Disclosure  . . . . . . . . . . . . . . . . .  43
   9.5.  Non-repudiation . . . . . . . . . . . . . . . . . . . . .  43
   9.6.  Replay Attacks  . . . . . . . . . . . . . . . . . . . . .  43
   9.7.  Compromised or Malicious Intermediary . . . . . . . . . .  44
 10. Internationalization Considerations . . . . . . . . . . . . .  44
 11. IANA Considerations . . . . . . . . . . . . . . . . . . . . .  44
   11.1.  URN Assignments  . . . . . . . . . . . . . . . . . . . .  44
   11.2.  Organization Identifier Namespace Registry . . . . . . .  45
 12. Formal Specification  . . . . . . . . . . . . . . . . . . . .  45
 13. References  . . . . . . . . . . . . . . . . . . . . . . . . .  54
   13.1.  Normative References . . . . . . . . . . . . . . . . . .  54
   13.2.  Informative References . . . . . . . . . . . . . . . . .  55
 Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . .  57
 Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  57

1. Introduction

 Service Providers (SPs) and enterprises use routing databases known
 as Registries to make session routing decisions for Voice over IP,
 SMS, and Multimedia Messaging Service (MMS) traffic exchanges.  This
 document is narrowly focused on the provisioning framework for these
 Registries.  This framework prescribes a way for an entity to
 provision session-related data into a Session Peering Provisioning
 Protocol (SPPP) Registry (or "Registry").  The data being provisioned
 can be optionally shared with other participating peering entities.
 The requirements and use cases driving this framework have been
 documented in [RFC6461].
 Three types of provisioning flows have been described in the use case
 document: client to Registry, Registry to local data repository, and
 Registry to Registry.  This document addresses client-to-Registry
 flow enabling the ability to provision Session Establishment Data

Cartwright, et al. Standards Track [Page 3] RFC 7877 SSPF August 2016

 (SED).  The framework that supports the flow of messages to
 facilitate client-to-Registry provisioning is referred to as the
 "Session Peering Provisioning Framework" (SPPF).
 The roles of the "client" and the "server" only apply to the
 connection, and those roles are not related in any way to the type of
 entity that participates in a protocol exchange.  For example, a
 Registry might also include a "client" when such a Registry initiates
 a connection (for example, for data distribution to an SSP).
  • ——–* *————* *————*

| | (1) Client | | (3) Registry | |

 | Client | ------------> |  Registry  |<------------->|  Registry  |
 |        |   to Registry |            |  to Registry  |            |
 *--------*               *------------*               *------------*
                               /  \                          \
                              /    \                          \
                             /      \                          \
                            /        \                          v
                           /          \                         ...
                          /            \
                         / (2) Distrib  \
                        / Registry data  \
                       /  to local data   \
                      V      store         V
                     +----------+       +----------+
                     |Local Data|       |Local Data|
                     |Repository|       |Repository|
                     +----------+       +----------+
              Figure 1: Three Registry Provisioning Flows
 A "terminating" SSP provisions SED into the Registry to be
 selectively shared with other peer SSPs.
 SED is typically used by various downstream SIP-signaling systems to
 route a call to the next hop associated with the called domain.
 These systems typically use a local data store ("Local Data
 Repository") as their source of session routing information.  More
 specifically, the SED is the set of parameters that the outgoing
 Signaling Path Border Elements (SBEs) need to initiate the session.
 See [RFC5486] for more details.
 A Registry may distribute the provisioned data into local data
 repositories or may additionally offer a central query-resolution
 service (not shown in the above figure) for query purposes.

Cartwright, et al. Standards Track [Page 4] RFC 7877 SSPF August 2016

 A key requirement for the SPPF is to be able to accommodate two basic
 deployment scenarios:
 1.  A resolution system returns a Lookup Function (LUF) that
     identifies the target domain to assist in call routing (as
     described in Section 4.3.3 of [RFC5486]).  In this case, the
     querying entity may use other means to perform the Location
     Routing Function (LRF), which in turn helps determine the actual
     location of the Signaling Function in that domain.
 2.  A resolution system returns an LRF that comprises the location
     (address) of the Signaling Function in the target domain (as
     described in [RFC5486]).
 In terms of framework design, SPPF is agnostic to the substrate
 protocol.  This document includes the specification of the data model
 and identifies, but does not specify, the means to enable protocol
 operations within a request and response structure.  That aspect of
 the specification has been delegated to the "protocol" specification
 for the framework.  To encourage interoperability, the framework
 supports extensibility aspects.
 In this document, an XML Schema is used to describe the building
 blocks of the SPPF and to express the data types, semantic
 relationships between the various data types, and various constraints
 as a binding construct.  However, a "protocol" specification is free
 to choose any data representation format as long as it meets the
 requirements laid out in the SPPF XML Schema Definition (XSD).  As an
 example, XML and JSON are two widely used data representation
 formats.
 This document is organized as follows:
 o  Section 2 provides the terminology
 o  Section 3 provides an overview of SPPF, including functional
    entities and a data model
 o  Section 4 specifies requirements for SPPF substrate protocols
 o  Section 5 describes the base framework data structures, the
    generic response types that MUST be supported by a conforming
    substrate "protocol" specification, and the basic object type from
    which most first-class objects extend
 o  Section 6 provides a detailed description of the data model object
    specifications

Cartwright, et al. Standards Track [Page 5] RFC 7877 SSPF August 2016

 o  Section 7 describes the operations that are supported by the data
    model
 o  Section 8 defines XML considerations XML parsers must meet to
    conform to this specification
 o  Sections 9 - 11 discuss security, internationalization, and IANA
    considerations, respectively
 o  Section 12 normatively defines the SPPF using its XSD.

2. Terminology

 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
 "OPTIONAL" in this document are to be interpreted as described in
 [RFC2119].
 This document reuses terms from [RFC3261], [RFC5486], use cases and
 requirements documented in [RFC6461], and the ENUM Validation
 Architecture [RFC4725].
 This document defines the following additional terms:
 SPPF:   Session Peering Provisioning Framework, which is the
    framework used by a substrate protocol to provision data into a
    Registry (see arrow labeled "1" in Figure 1 of [RFC6461]).  It is
    the primary scope of this document.
 Client:   In the context of SPPF, this is an application that
    initiates a provisioning request.  It is sometimes referred to as
    a "Registry client".
 Server:   In the context of SPPF, this is an application that
    receives a provisioning request and responds accordingly.
 Registry:   The Registry operates a master database of SED for one or
    more Registrants.
 Registrant:   The definition of a Registrant is based on [RFC4725].
    It is the end user, person, or organization that is the "holder"
    of the SED being provisioned into the Registry by a Registrar.
    For example, in [RFC6461], a Registrant is pictured as an SP in
    Figure 2.
    Within the confines of a Registry, a Registrant is uniquely
    identified by the "rant" element.

Cartwright, et al. Standards Track [Page 6] RFC 7877 SSPF August 2016

 Registrar:   The definition of a Registrar is based on [RFC4725].  It
    is an entity that performs provisioning operations on behalf of a
    Registrant by interacting with the Registry via SPPF operations.
    In other words, the Registrar is the SPPF client.  The Registrar
    and Registrant roles are logically separate to allow, but not
    require, a single Registrar to perform provisioning operations on
    behalf of more than one Registrant.
 Peering Organization:   A peering organization is an entity to which
    a Registrant's SED Groups are made visible using the operations of
    SPPF.

3. Framework High-Level Design

 This section introduces the structure of the data model and provides
 the information framework for the SPPF.  The data model is defined
 along with all the objects manipulated by a conforming substrate
 protocol and their relationships.

3.1. Framework Data Model

 The data model illustrated and described in Figure 2 defines the
 logical objects and the relationships between these objects supported
 by SPPF.  SPPF defines protocol operations through which an SPPF
 client populates a Registry with these logical objects.  SPPF clients
 belonging to different Registrars may provision data into the
 Registry using a conforming substrate protocol that implements these
 operations
 The logical structure presented below is consistent with the
 terminology and requirements defined in [RFC6461].

Cartwright, et al. Standards Track [Page 7] RFC 7877 SSPF August 2016

     +-------------+                        +-----------------+
     | All object  |                        |Egress Route:    |
     | types       |                   0..n | rant,           |
     +-------------+                     +--| egrRteName,     |
           |0..n                        /   | pref,           |
           |                           /    | regxRewriteRule,|
           |2                         /     | ingrSedGrp,     |
 +----------------------+            /      | svcs            |
 |Organization:         |           /       +-----------------+
 | orgId                |          /
 +----------------------+         /
        |0..n                    /
        |                       /        ("rant" = Registrant)
        |A SED Group is        /
        |associated with      /
        |zero or more        /              +---[abstract]----+
        |peering            /               | SED Record:     |
        |organizations     /                |  rant,          |
        |                 /                 |  sedName,       |0..n
        |0..n            /                  |  sedFunction,   |------|
 +--------+--------------+0..n          0..n|  isInSvc,       |      |
 |SED Group:             |------------------|  ttl            |      |
 |  rant,                |                  +-----------------+      |
 |  sedGrpName,          |                      ^ Various types      |
 |  isInSvc,             |                      | of SED Records     |
 |  sedRecRef,           |                      |                    |
 |  peeringOrg,          |                +-----+------------+       |
 |  sourceIdent,         |                |        |         |       |
 |  priority,            |             +----+  +-------+  +----+     |
 |  dgName               |             | URI|  | NAPTR |  | NS |     |
 +-----------------------+             +----+  +-------+  +----+     |
        |0..n                                                        |
        |                                 +-----[abstract]------+    |
        |0..n                             |Public Identifier:   |    |
    +----------------------+0..n      0..n|  rant,              |    |
    | Dest Group:          |--------------|  publicIdentifier,  |    |
    |   rant,              |              |  dgName             |    |
    |   dgName             |              |                     |    |
    +----------------------+              +---------------------+    |
                                                   ^ Various types   |
               +---------+-------+------+----------+ of Public       |
               |         |       |      |          | Identifiers     |
            +------+  +-----+  +-----+ +-----+  +------+             |
            |  URI |  | TNP |  | TNR | | RN  |  |  TN  |-------------|
            +------+  +-----+  +-----+ +-----+  +------+  0..n
                    Figure 2: Framework Data Model

Cartwright, et al. Standards Track [Page 8] RFC 7877 SSPF August 2016

 The objects and attributes that comprise the data model can be
 described as follows (objects listed from the bottom up):
 o  Public Identifier:
    From a broad perspective, a Public Identifier is a well-known
    attribute that is used as the key to perform resolution lookups.
    Within the context of SPPF, a Public Identifier object can be a
    Telephone Number (TN), a range of TNs, a Public Switched Telephone
    Network (PSTN) Routing Number (RN), a TN prefix, or a URI.
    An SPPF Public Identifier may be a member of zero or more
    Destination Groups to create logical groupings of Public
    Identifiers that share a common set of SED (e.g., routes).
    A TN Public Identifier may optionally be associated with zero or
    more individual SED Records.  This ability for a Public Identifier
    to be directly associated with a SED Record, as opposed to forcing
    membership in one or more Destination Groups, supports use cases
    where the SED Record contains data specifically tailored to an
    individual TN Public Identifier.
 o  Destination Group:
    A named logical grouping of zero or more Public Identifiers that
    can be associated with one or more SED Groups for the purpose of
    facilitating the management of their common SED.
 o  SED Group:
    A SED Group contains a set of SED Record references, a set of
    Destination Group references, and a set of peering organization
    identifiers.  This is used to establish a three-part relationship
    between a set of Public Identifiers, the SED shared across these
    Public Identifiers, and the list of peering organizations whose
    query responses from the resolution system may include the SED
    contained in a given SED Group.  In addition, the sourceIdent
    element within a SED Group, in concert with the set of peering
    organization identifiers, enables fine-grained source-based
    routing.  For further details about the SED Group and source-based
    routing, refer to the definitions and descriptions in Section 6.1.
 o  SED Record:
    A SED Record contains the data that a resolution system returns in
    response to a successful query for a Public Identifier.  SED
    Records are generally associated with a SED Group when the SED
    within is not specific to a Public Identifier.
    To support the use cases defined in [RFC6461], the SPPF defines
    three types of SED Records: URIType, NAPTRType, and NSType.  These
    SED Records extend the abstract type SedRecType and inherit the

Cartwright, et al. Standards Track [Page 9] RFC 7877 SSPF August 2016

    common attribute "priority" that is meant for setting precedence
    across the SED Records defined within a SED Group in a protocol-
    agnostic fashion.
 o  Egress Route:
    In a high-availability environment, the originating SSP likely has
    more than one egress path to the ingress SBE of the target SSP.
    The Egress Route allows the originating SSP to choose a specific
    egress SBE to be associated with the target ingress SBE.  The
    "svcs" element specifies ENUM services (e.g., E2U+pstn:sip+sip)
    that are used to identify the SED Records associated with the SED
    Group that will be modified by the originating SSP.
 o  Organization:
    An Organization is an entity that may fulfill any combination of
    three roles: Registrant, Registrar, and peering organization.  All
    objects in SPPF are associated with two organization identifiers
    to identify each object's Registrant and Registrar.  A SED Group
    object is also associated with a set of zero or more organization
    identifiers that identify the peering organization(s) whose
    resolution query responses may include the SED defined in the SED
    Records within that SED Group.  A peering organization is an
    entity with which the Registrant intends to share the SED data.

3.2. Time Value

 Some request and response messages in SPPF include a time value or
 values defined as type xs:dateTime, a built-in W3C XML Schema
 Datatype.  Use of an unqualified local time value is disallowed as it
 can lead to interoperability issues.  The value of a time attribute
 MUST be expressed in Coordinated Universal Time (UTC) format without
 the time-zone digits.
 "2010-05-30T09:30:10Z" is an example of an acceptable time value for
 use in SPPF messages.  "2010-05-30T06:30:10+3:00" is a valid UTC time
 but is not acceptable for use in SPPF messages.

3.3. Extensibility

 The framework contains various points of extensibility in the form of
 the "ext" elements.  Extensions used beyond the scope of private SPPF
 installations need to be documented in an RFC, and the first such
 extension is expected to define an IANA registry, holding a list of
 documented extensions.

Cartwright, et al. Standards Track [Page 10] RFC 7877 SSPF August 2016

4. Substrate Protocol Requirements

 This section provides requirements for substrate protocols suitable
 to carry SPPF.  More specifically, this section specifies the
 services, features, and assumptions that SPPF delegates to the chosen
 substrate and envelope technologies.

4.1. Mandatory Substrate

 None of the existing transport protocols carried directly over IP,
 appearing as "Protocol" in the IPv4 headers or "Next Header" in the
 IPv6 headers, meet the requirements listed in this section to carry
 SPPF.
 Therefore, one choice to carry SPPF has been provided in "Session
 Peering Provisioning (SPP) Protocol over SOAP" [RFC7878], using SOAP
 as the substrate.  To encourage interoperability, the SPPF server
 MUST provide support for this protocol.  With time, it is possible
 that other choices may surface that comply with the requirements
 discussed above.

4.2. Connection Oriented

 The SPPF follows a model where a client establishes a connection to a
 server in order to further exchange SPPF messages over such a point-
 to-point connection.  Therefore, a substrate protocol for SPPF will
 be connection oriented.

4.3. Request and Response Model

 Provisioning operations in SPPF follow the request-response model,
 where a client sends a request message to initiate a transaction and
 the server sends a response.  Multiple subsequent request-response
 exchanges MAY be performed over a single persistent connection.
 Therefore, a substrate protocol for SPPF will follow the request-
 response model by ensuring a response is sent to the request
 initiator.

4.4. Connection Lifetime

 Some use cases involve provisioning a single request to a network
 element.  Connections supporting such provisioning requests might be
 short-lived, and may be established only on demand, for the duration
 of a few seconds.  Other use cases involve provisioning either a
 large dataset or a constant stream of small updates, both of which
 would likely require long-lived connections, spanning multiple hours
 or even days.

Cartwright, et al. Standards Track [Page 11] RFC 7877 SSPF August 2016

 Therefore, a protocol suitable for SPPF SHOULD be able to support
 both short-lived and long-lived connections.

4.5. Authentication

 All SPPF objects are associated with a Registrant identifier.  An
 SPPF client provisions SPPF objects on behalf of Registrants.  An
 authenticated SPP client is a Registrar.  Therefore, the SPPF
 substrate protocol MUST provide means for an SPPF server to
 authenticate an SPPF client.

4.6. Authorization

 After successful authentication of the SPPF client as a Registrar,
 the Registry performs authorization checks to determine if the
 Registrar is authorized to act on behalf of the Registrant whose
 identifier is included in the SPPF request.  Refer to Section 9 for
 further guidance.

4.7. Confidentiality and Integrity

 SPPF objects that the Registry manages can be private in nature.
 Therefore, the substrate protocol MUST provide means for data
 integrity protection.
 If the data is compromised in-flight between the SPPF client and
 Registry, it will seriously affect the stability and integrity of the
 system.  Therefore, the substrate protocol MUST provide means for
 data integrity protection.

4.8. Near Real Time

 Many use cases require responses in near real time from the server
 (in the range of a few multiples of round-trip time between the
 server and client).  Therefore, a Data for Reachability of
 Inter-/Intra-NetworK SIP (DRINKS) substrate protocol MUST support
 near real-time responses to requests submitted by the client.

4.9. Request and Response Sizes

 Use of SPPF may involve simple updates that may consist of a small
 number of bytes, such as the update of a single Public Identifier.
 Other provisioning operations may constitute a large dataset, as in
 adding millions of records to a Registry.  As a result, a suitable
 substrate protocol for SPPF SHOULD accommodate datasets of various
 sizes.

Cartwright, et al. Standards Track [Page 12] RFC 7877 SSPF August 2016

4.10. Request and Response Correlation

 A substrate protocol suitable for SPPF MUST allow responses to be
 correlated with requests.

4.11. Request Acknowledgement

 Data transported in the SPPF is likely crucial for the operation of
 the communication network that is being provisioned.  An SPPF client
 responsible for provisioning SED to the Registry has a need to know
 if the submitted requests have been processed correctly.
 Failed transactions can lead to situations where a subset of Public
 Identifiers or even SSPs might not be reachable or the provisioning
 state of the network is inconsistent.
 Therefore, a substrate protocol for SPPF MUST provide a response for
 each request, so that a client can identify whether a request
 succeeded or failed.

5. Base Framework Data Structures and Response Codes

 SPPF contains some common data structures for most of the supported
 object types.  This section describes these common data structures.

5.1. Basic Object Type and Organization Identifiers

 All first-class objects extend the type BasicObjType.  It consists of
 the Registrant organization, the Registrar organization, the date and
 time of object creation, and the last date and time the object was
 modified.  The Registry MUST store the date and time of the object
 creation and modification, if applicable, for all Get operations (see
 Section 7).  If the client passed in either date or time values, the
 Registry MUST ignore it.  The Registrar performs the SPPF operations
 on behalf of the Registrant, the organization that owns the object.
 <complexType name="BasicObjType" abstract="true">
  <sequence>
   <element name="rant" type="sppfb:OrgIdType"/>
   <element name="rar" type="sppfb:OrgIdType"/>
   <element name="cDate" type="dateTime" minOccurs="0"/>
   <element name="mDate" type="dateTime" minOccurs="0"/>
   <element name="ext" type="sppfb:ExtAnyType" minOccurs="0"/>
  </sequence>
 </complexType>

Cartwright, et al. Standards Track [Page 13] RFC 7877 SSPF August 2016

 The identifiers used for Registrants (rant) and Registrars (rar) are
 instances of OrgIdType.  The OrgIdType is defined as a string and all
 OrgIdType instances MUST follow the textual convention:
 "namespace:value" (for example, "iana-en:32473").  Specifically:
 Strings used as OrgIdType Namespace identifiers MUST conform to the
 following syntax in the Augmented Backus-Naur Form (ABNF) [RFC5234].
       namespace = ALPHA *(ALPHA/DIGIT/"-")
 See Section 11 for the corresponding IANA registry definition.

5.2. Various Object Key Types

 The SPPF data model contains various object relationships.  In some
 cases, these object relationships are established by embedding the
 unique identity of the related object inside the relating object.
 Note that an object's unique identity is required to Delete or Get
 the details of an object.  The following subsections normatively
 define the various object keys in SPPF and the attributes of those
 keys.
 "Name" attributes that are used as components of object key types
 MUST be compared using the toCasefold() function, as specified in
 Section 3.13 of [Unicode6.1] (or a newer version of Unicode).  This
 function performs case-insensitive comparisons.

5.2.1. Generic Object Key Type

 Most objects in SPPF are uniquely identified by an object key that
 has the object's name, type, and Registrant's organization ID as
 attributes.  The abstract type called ObjKeyType is where this unique
 identity is housed.  Any concrete representation of the ObjKeyType
 MUST contain the following:
    Object Name: The name of the object.
    Registrant ID: The unique organization ID that identifies the
    Registrant.
    Type: The value that represents the type of SPPF object.  This is
    required as different types of objects in SPPF, that belong to the
    same Registrant, can have the same name.

Cartwright, et al. Standards Track [Page 14] RFC 7877 SSPF August 2016

 The structure of abstract ObjKeyType is as follows:
 <complexType name="ObjKeyType" abstract="true">
  <annotation>
   <documentation>
   ---- Generic type that represents the
        key for various objects in SPPF. ----
   </documentation>
  </annotation>
 </complexType>

5.2.2. Derived Object Key Types

 The SPPF data model contains certain objects that are uniquely
 identified by attributes, different from or in addition to the
 attributes in the generic object key described in the previous
 section.  Object keys of this kind are derived from the abstract
 ObjKeyType and defined in their own abstract key types.  Because
 these object key types are abstract, they MUST be specified in a
 concrete form in any SPPF-conforming substrate "protocol"
 specification.  These are used in Delete and Get operations and may
 also be used in Accept and Reject operations.
 Following are the derived object keys in an SPPF data model:
 o  SedGrpOfferKeyType: This uniquely identifies a SED Group object
    offer.  This key type extends from ObjKeyType and MUST also have
    the organization ID of the Registrant to whom the object is being
    offered as one of its attributes.  In addition to the Delete and
    Get operations, these key types are used in Accept and Reject
    operations on a SED Group Offer object.  The structure of abstract
    SedGrpOfferKeyType is as follows:
 <complexType name="SedGrpOfferKeyType"
 abstract="true">
     <complexContent>
         <extension base="sppfb:ObjKeyType">
             <annotation>
     <documentation>
     ---- Generic type that represents
          the key for an object offer. ----
     </documentation>
    </annotation>
   </extension>
  </complexContent>
 </complexType>

Cartwright, et al. Standards Track [Page 15] RFC 7877 SSPF August 2016

    A SED Group Offer object MUST use SedGrpOfferKeyType.  Refer to
    Section 6.5 for a description of the SED Group Offer object.
 o  PubIdKeyType: This uniquely identifies a Public Identity object.
    This key type extends from the abstract ObjKeyType.  Any concrete
    definition of PubIdKeyType MUST contain the elements that identify
    the value and type of Public Identity and also contain the
    organization ID of the Registrant that is the owner of the Public
    Identity object.  A Public Identity object in SPPF is uniquely
    identified by the Registrant's organization ID, the value of the
    Public Identity, and the type of the Public Identity object.
    Consequently, any concrete representation of the PubIdKeyType MUST
    contain the following attributes:
  • Registrant ID: The unique organization ID that identifies the

Registrant.

  • Value: The value of the Public Identity.
  • Type: The type of the Public Identity object.
    The PubIdKeyType is used in Delete and Get operations on a Public
    Identifier object.
 o  The structure of abstract PubIdKeyType is as follows:
 <complexType name="PubIdKeyType" abstract="true">
  <complexContent>
   <extension base="sppfb:ObjKeyType">
    <annotation>
     <documentation>
     ---- Generic type that represents the key for a Pub ID. ----
     </documentation>
    </annotation>
   </extension>
  </complexContent>
 </complexType>
 A Public Identity object MUST use attributes of PubIdKeyType for its
 unique identification.  Refer to Section 6 for a description of a
 Public Identity object.

5.3. Response Message Types

 The following table contains the list of response types that MUST be
 defined for a substrate protocol used to carry SPPF.  An SPPF server
 MUST implement all of the following at minimum.

Cartwright, et al. Standards Track [Page 16] RFC 7877 SSPF August 2016

 +---------------------+---------------------------------------------+
 | Response Type       | Description                                 |
 +---------------------+---------------------------------------------+
 | Request succeeded   | A given request succeeded.                  |
 | Request syntax      | The syntax of a given request was found to  |
 | invalid             | be invalid.                                 |
 | Request too large   | The count of entities in the request is     |
 |                     | larger than the server is willing or able   |
 |                     | to process.                                 |
 | Version not         | The server does not support the version of  |
 | supported           | the SPPF protocol specified in the request. |
 | Command invalid     | The operation and/or command being          |
 |                     | requested by the client is invalid and/or   |
 |                     | not supported by the server.                |
 | System temporarily  | The SPPF server is temporarily not          |
 | unavailable         | available to serve the client request.      |
 | Unexpected internal | The SPPF server encountered an unexpected   |
 | system or server    | error that prevented the server from        |
 | error               | fulfilling the request.                     |
 | Attribute value     | The SPPF server encountered an attribute or |
 | invalid             | property in the request that had an         |
 |                     | invalid/bad value.  Optionally, the         |
 |                     | specification MAY provide a way to indicate |
 |                     | the Attribute Name and the Attribute Value  |
 |                     | to identify the object that was found to be |
 |                     | invalid.                                    |
 | Object does not     | An object present in the request does not   |
 | exist               | exist on the SPPF server. Optionally, the   |
 |                     | specification MAY provide a way to indicate |
 |                     | the Attribute Name and the Attribute Value  |
 |                     | that identifies the nonexistent object.     |
 | Object status or    | The operation requested on an object        |
 | ownership does not  | present in the request cannot be performed  |
 | allow for operation | because the object is in a status that does |
 |                     | not allow said operation, or the user       |
 |                     | requesting the operation is not authorized  |
 |                     | to perform said operation on the object.    |
 |                     | Optionally, the specification MAY provide a |
 |                     | way to indicate the Attribute Name and the  |
 |                     | Attribute Value that identifies the object. |
 +---------------------+---------------------------------------------+
                        Table 1: Response Types

Cartwright, et al. Standards Track [Page 17] RFC 7877 SSPF August 2016

 When the response messages are "parameterized" with the Attribute
 Name and Attribute Value, then the use of these parameters MUST
 adhere to the following rules:
 o  Any value provided for the Attribute Name parameter MUST be an
    exact XSD element name of the protocol data element to which the
    response message is referring.  For example, valid values for
    "attribute name" are "dgName", "sedGrpName", "sedRec", etc.
 o  The value for Attribute Value MUST be the value of the data
    element to which the preceding Attribute Name refers.
 o  Response type "Attribute value invalid" MUST be used whenever an
    element value does not adhere to data validation rules.
 o  Response types "Attribute value invalid" and "Object does not
    exist" MUST NOT be used interchangeably.  Response type "Object
    does not exist" MUST be returned by an Update/Del/Accept/Reject
    operation when the data element(s) used to uniquely identify a
    preexisting object does not exist.  If the data elements used to
    uniquely identify an object are malformed, then response type
    "Attribute value invalid" MUST be returned.

6. Framework Data Model Objects

 This section provides a description of the specification of each
 supported data model object (the nouns) and identifies the commands
 (the verbs) that MUST be supported for each data model object.
 However, the specification of the data structures necessary to
 support each command is delegated to an SPPF-conforming substrate
 "protocol" specification.

6.1. Destination Group

 A Destination Group represents a logical grouping of Public
 Identifiers with common SED.  The substrate protocol MUST support the
 ability to Add, Get, and Delete Destination Groups (refer to
 Section 7 for a generic description of various operations).
 A Destination Group object MUST be uniquely identified by attributes
 as defined in the description of "ObjKeyType" in "Generic Object Key
 Type" (Section 5.2.1 of this document).

Cartwright, et al. Standards Track [Page 18] RFC 7877 SSPF August 2016

 The DestGrpType object structure is defined as follows:
 <complexType name="DestGrpType">
  <complexContent>
   <extension base="sppfb:BasicObjType">
    <sequence>
     <element name="dgName" type="sppfb:ObjNameType"/>
    </sequence>
   </extension>
  </complexContent>
 </complexType>
 The DestGrpType object is composed of the following elements:
 o  base: All first-class objects extend BasicObjType (see
    Section 5.1).
 o  dgName: The character string that contains the name of the
    Destination Group.
 o  ext: Point of extensibility described in Section 3.3.

6.2. Public Identifier

 A Public Identifier is the search key used for locating the SED.  In
 many cases, a Public Identifier is attributed to the end user who has
 a retail relationship with the SP or Registrant organization.  SPPF
 supports the notion of the carrier-of-record as defined in [RFC5067].
 Therefore, the Registrant under which the Public Identifier is being
 created can optionally claim to be a carrier-of-record.
 SPPF identifies three types of Public Identifiers: TNs, RNs, and
 URIs.  SPPF provides structures to manage a single TN, a contiguous
 range of TNs, and a TN prefix.  The substrate protocol MUST support
 the ability to Add, Get, and Delete Public Identifiers (refer to
 Section 7 for a generic description of various operations).
 A Public Identity object MUST be uniquely identified by attributes as
 defined in the description of "PubIdKeyType" in Section 5.2.2.

Cartwright, et al. Standards Track [Page 19] RFC 7877 SSPF August 2016

 The abstract XSD type PubIdType is a generalization for the concrete
 Public Identifier schema types.  The PubIdType element "dgName"
 represents the name of a Destination Group of which a given Public
 Identifier may be a member.  Note that this element may be present
 multiple times so that a given Public Identifier may be a member of
 multiple Destination Groups.  The PubIdType object structure is
 defined as follows:
 <complexType name="PubIdType" abstract="true">
  <complexContent>
   <extension base="sppfb:BasicObjType">
    <sequence>
     <element name="dgName" type="sppfb:ObjNameType"
              minOccurs="0" maxOccurs="unbounded"/>
    </sequence>
   </extension>
  </complexContent>
 </complexType>
 A Public Identifier may be a member of zero or more Destination
 Groups.  When a Public Identifier is a member of a Destination Group,
 it is intended to be associated with SED through the SED Group(s)
 that is associated with the Destination Group.  When a Public
 Identifier is not member of any Destination Group, it is intended to
 be associated with SED through the SED Records that are directly
 associated with the Public Identifier.

Cartwright, et al. Standards Track [Page 20] RFC 7877 SSPF August 2016

 A TN is provisioned using the TNType, an extension of PubIdType.
 Each TNType object is uniquely identified by the combination of its
 value contained within the <tn> element and its Registrant ID.
 TNType is defined as follows:
 <complexType name="TNType">
  <complexContent>
   <extension base="sppfb:PubIdType">
    <sequence>
     <element name="tn" type="sppfb:NumberValType"/>
     <element name="corInfo" type="sppfb:CORInfoType" minOccurs="0"/>
     <element name="sedRecRef" type="sppfb:SedRecRefType"
              minOccurs="0" maxOccurs="unbounded"/>
    </sequence>
   </extension>
  </complexContent>
 </complexType>
 <complexType name="CORInfoType">
  <sequence>
    <element name="corClaim" type="boolean" default="true"/>
    <element name="cor" type="boolean" default="false" minOccurs="0"/>
    <element name="corDate" type="dateTime" minOccurs="0"/>
  </sequence>
 </complexType>
 <simpleType name="NumberValType">
  <restriction base="token">
   <maxLength value="20"/>
   <pattern value="\+?\d\d*"/>
  </restriction>
 </simpleType>
 TNType consists of the following attributes:
 o  tn: Telephone number to be added to the Registry.
 o  sedRecRef: Optional reference to SED Records that are directly
    associated with the TN Public Identifier.  Following the SPPF data
    model, the SED Record could be a protocol-agnostic URIType or
    another type.
 o  corInfo: corInfo is an optional parameter of type CORInfoType that
    allows the Registrant organization to set forth a claim to be the
    carrier-of-record (see [RFC5067]).  This is done by setting the
    value of the <corClaim> element of the CORInfoType object
    structure to "true".  The other two parameters of the CORInfoType,
    <cor> and <corDate>, are set by the Registry to describe the

Cartwright, et al. Standards Track [Page 21] RFC 7877 SSPF August 2016

    outcome of the carrier-of-record claim by the Registrant.  In
    general, inclusion of the <corInfo> parameter is useful if the
    Registry has the authority information, such as the number
    portability data, etc., in order to qualify whether the Registrant
    claim can be satisfied.  If the carrier-of-record claim disagrees
    with the authority data in the Registry, whether or not a TN Add
    operation fails is a matter of policy and is beyond the scope of
    this document.
 An RN is provisioned using the RNType, an extension of PubIDType.
 The Registrant organization can add the RN and associate it with the
 appropriate Destination Group(s) to share the route information.
 This allows SSPs to use the RN search key to derive the Ingress
 Routes for session establishment at the runtime resolution process
 (see [RFC6116]).  Each RNType object is uniquely identified by the
 combination of its value inside the <rn> element and its Registrant
 ID.  RNType is defined as follows:
 <complexType name="RNType">
  <complexContent>
   <extension base="sppfb:PubIdType">
    <sequence>
     <element name="rn" type="sppfb:NumberValType"/>
     <element name="corInfo" type="sppfb:CORInfoType" minOccurs="0"/>
    </sequence>
   </extension>
  </complexContent>
 </complexType>
 RNType has the following attributes:
 o  rn: The RN used as the search key.
 o  corInfo: corInfo is an optional parameter of type CORInfoType that
    allows the Registrant organization to set forth a claim to be the
    carrier-of-record (see [RFC5067]).
 TNRType structure is used to provision a contiguous range of TNs.
 The object definition requires a starting TN and an ending TN that
 together define the span of the TN range, including the starting and
 ending TN.  Use of TNRType is particularly useful when expressing a
 TN range that does not include all the TNs within a TN block or
 prefix.  The TNRType definition accommodates the open number plan as
 well such that the TNs that fall in the range between the start and
 end TN may include TNs with different length variance.  Whether the
 Registry can accommodate the open number plan semantics is a matter
 of policy and is beyond the scope of this document.  Each TNRType
 object is uniquely identified by the combination of its value that,

Cartwright, et al. Standards Track [Page 22] RFC 7877 SSPF August 2016

 in turn, is a combination of the <startTn> and <endTn> elements and
 its Registrant ID.  The TNRType object structure definition is as
 follows:
 <complexType name="TNRType">
  <complexContent>
   <extension base="sppfb:PubIdType">
    <sequence>
     <element name="range" type="sppfb:NumberRangeType"/>
     <element name="corInfo" type="sppfb:CORInfoType" minOccurs="0"/>
    </sequence>
   </extension>
  </complexContent>
 </complexType>
 <complexType name="NumberRangeType">
  <sequence>
   <element name="startTn" type="sppfb:NumberValType"/>
   <element name="endTn" type="sppfb:NumberValType"/>
  </sequence>
 </complexType>
 TNRType has the following attributes:
 o  startTn: The starting TN in the TN range.
 o  endTn: The last TN in the TN range.
 o  corInfo: corInfo is an optional parameter of type CORInfoType that
    allows the Registrant organization to set forth a claim to be the
    carrier-of-record (see [RFC5067]).

Cartwright, et al. Standards Track [Page 23] RFC 7877 SSPF August 2016

 In some cases, it is useful to describe a set of TNs with the help of
 the first few digits of the TN, also referred to as the TN prefix or
 a block.  A given TN prefix may include TNs with different length
 variance in support of the open number plan.  Once again, whether the
 Registry supports the open number plan semantics is a matter of
 policy, and it is beyond the scope of this document.  The TNPType
 data structure is used to provision a TN prefix.  Each TNPType object
 is uniquely identified by the combination of its value in the
 <tnPrefix> element and its Registrant ID.  TNPType is defined as
 follows:
 <complexType name="TNPType">
  <complexContent>
   <extension base="sppfb:PubIdType">
    <sequence>
     <element name="tnPrefix" type="sppfb:NumberValType"/>
     <element name="corInfo" type="sppfb:CORInfoType" minOccurs="0"/>
    </sequence>
   </extension>
  </complexContent>
 </complexType>
 TNPType consists of the following attributes:
 o  tnPrefix: The TN prefix.
 o  corInfo: corInfo is an optional parameter of type CORInfoType that
    allows the Registrant organization to set forth a claim to be the
    carrier-of-record (see [RFC5067]).
 In some cases, a Public Identifier may be a URI, such as an email
 address.  The URIPubIdType object is comprised of the data element
 necessary to house such Public Identifiers.  Each URIPubIdType object
 is uniquely identified by the combination of its value in the <uri>
 element and its Registrant ID.  URIPubIdType is defined as follows:
 <complexType name="URIPubIdType">
  <complexContent>
   <extension base="sppfb:PubIdType">
    <sequence>
     <element name="uri" type="anyURI"/>
     <element name="ext" type="sppfb:ExtAnyType" minOccurs="0"/>
    </sequence>
   </extension>
  </complexContent>
 </complexType>

Cartwright, et al. Standards Track [Page 24] RFC 7877 SSPF August 2016

 URIPubIdType consists of the following attributes:
 o  uri: The value that acts as the Public Identifier.
 o  ext: Point of extensibility described in Section 3.3.

6.3. SED Group

 SED Group is a grouping of one or more Destination Groups, the common
 SED Records, and the list of peer organizations with access to the
 SED Records associated with a given SED Group.  It is this indirect
 linking of Public Identifiers to their SED that significantly
 improves the scalability and manageability of the peering data.
 Additions and changes to SED information are reduced to a single
 operation on a SED Group or SED Record rather than millions of data
 updates to individual Public Identifier records that individually
 contain their peering data.  The substrate protocol MUST support the
 ability to Add, Get, and Delete SED Groups (refer to Section 7 for a
 generic description of various operations).
 A SED Group object MUST be uniquely identified by attributes as
 defined in the description of "ObjKeyType" in "Generic Object Key
 Type" (Section 5.2.1 of this document).

Cartwright, et al. Standards Track [Page 25] RFC 7877 SSPF August 2016

 The SedGrpType object structure is defined as follows:
 <complexType name="SedGrpType">
  <complexContent>
   <extension base="sppfb:BasicObjType">
    <sequence>
     <element name="sedGrpName" type="sppfb:ObjNameType"/>
     <element name="sedRecRef" type="sppfb:SedRecRefType"
              minOccurs="0" maxOccurs="unbounded"/>
     <element name="dgName" type="sppfb:ObjNameType"
              minOccurs="0" maxOccurs="unbounded"/>
     <element name="peeringOrg" type="sppfb:OrgIdType"
              minOccurs="0" maxOccurs="unbounded"/>
     <element name="sourceIdent" type="sppfb:SourceIdentType"
              minOccurs="0" maxOccurs="unbounded"/>
     <element name="isInSvc" type="boolean"/>
     <element name="priority" type="unsignedShort"/>
     <element name="ext" type="sppfb:ExtAnyType" minOccurs="0"/>
    </sequence>
   </extension>
  </complexContent>
 </complexType>
 <complexType name="SedRecRefType">
  <sequence>
   <element name="sedKey" type="sppfb:ObjKeyType"/>
   <element name="priority" type="unsignedShort"/>
   <element name="ext" type="sppfb:ExtAnyType" minOccurs="0"/>
  </sequence>
 </complexType>
 The SedGrpType object is composed of the following elements:
 o  base: All first-class objects extend BasicObjType (see
    Section 5.1).
 o  sedGrpName: The character string that contains the name of the SED
    Group.  It uniquely identifies this object within the context of
    the Registrant ID (a child element of the base element as
    described above).
 o  sedRecRef: Set of zero or more objects of type SedRecRefType that
    house the unique keys of the SED Records (containing the SED) that
    the SedGrpType object refers to and their relative priority within
    the context of this SED Group.

Cartwright, et al. Standards Track [Page 26] RFC 7877 SSPF August 2016

 o  dgName: Set of zero or more names of DestGrpType object instances.
    Each dgName name, in association with this SED Group's Registrant
    ID, uniquely identifies a DestGrpType object instance whose
    associated Public Identifiers are reachable using the SED housed
    in this SED Group.  An intended side effect of this is that a SED
    Group cannot provide session establishment information for a
    Destination Group belonging to another Registrant.
 o  peeringOrg: Set of zero or more peering organization IDs that have
    accepted an offer to receive this SED Group's information.  Note
    that this identifier "peeringOrg" is an instance of OrgIdType.
    The set of peering organizations in this list is not directly
    settable or modifiable using the addSedGrpsRqst operation.  This
    set is instead controlled using the SED Offer and Accept
    operations.
 o  sourceIdent: Set of zero or more SourceIdentType object instances.
    These objects, described further below, house the source
    identification schemes and identifiers that are applied at
    resolution time as part of source-based routing algorithms for the
    SED Group.
 o  isInSvc: A boolean element that defines whether this SED Group is
    in service.  The SED contained in a SED Group that is in service
    is a candidate for inclusion in resolution responses for Public
    Identities residing in the Destination Group associated with this
    SED Group.  The session establishment information contained in a
    SED Group that is not in service is not a candidate for inclusion
    in resolution responses.
 o  priority: Priority value that can be used to provide a relative
    value weighting of one SED Group over another.  The manner in
    which this value is used, perhaps in conjunction with other
    factors, is a matter of policy.
 o  ext: Point of extensibility described in Section 3.3.
 As described above, the SED Group contains a set of references to SED
 Record objects.  A SED Record object is based on an abstract type:
 SedRecType.  The concrete types that use SedRecType as an extension
 base are NAPTRType, NSType, and URIType.  The definitions of these
 types are included in "SED Record" (Section 6.4 of this document).
 The SedGrpType object provides support for source-based routing via
 the peeringOrg data element and more granular source-based routing
 via the source identity element.  The source identity element
 provides the ability to specify zero or more of the following in
 association with a given SED Group: a regular expression that is

Cartwright, et al. Standards Track [Page 27] RFC 7877 SSPF August 2016

 matched against the resolution client IP address, a regular
 expression that is matched against the root domain name(s), and/or a
 regular expression that is matched against the calling party URI(s).
 The result will be that, after identifying the visible SED Groups
 whose associated Destination Group(s) contains the lookup key being
 queried and whose peeringOrg list contains the querying
 organization's organization ID, the resolution server will evaluate
 the characteristics of the Source URI, Source IP address, and root
 domain of the lookup key being queried.  The resolution server then
 compares these criteria against the source identity criteria
 associated with the SED Groups.  The SED contained in SED Groups that
 have source-based routing criteria will only be included in the
 resolution response if one or more of the criteria matches the source
 criteria from the resolution request.  The source identity data
 element is of type SourceIdentType, whose structure is defined as
 follows:
 <complexType name="SourceIdentType">
  <sequence>
   <element name="sourceIdentRegex" type="sppfb:RegexType"/>
   <element name="sourceIdentScheme"
            type="sppfb:SourceIdentSchemeType"/>
   <element name="ext" type="sppfb:ExtAnyType" minOccurs="0"/>
  </sequence>
 </complexType>
 <simpleType name="SourceIdentSchemeType">
  <restriction base="token">
   <enumeration value="uri"/>
   <enumeration value="ip"/>
   <enumeration value="rootDomain"/>
  </restriction>
 </simpleType>
 The SourceIdentType object is composed of the following data
 elements:
 o  sourceIdentScheme: The source identification scheme that this
    source identification criteria applies to and that the associated
    sourceIdentRegex should be matched against.
 o  sourceIdentRegex: The regular expression that should be used to
    test for a match against the portion of the resolution request
    that is dictated by the associated sourceIdentScheme.
 o  ext: Point of extensibility described in Section 3.3.

Cartwright, et al. Standards Track [Page 28] RFC 7877 SSPF August 2016

6.4. SED Record

 SED Group represents a combined grouping of SED Records that define
 SED.  However, SED Records need not be created to just serve a single
 SED Group.  SED Records can be created and managed to serve multiple
 SED Groups.  As a result, a change, for example, to the properties of
 a network node used for multiple routes would necessitate just a
 single update operation to change the properties of that node.  The
 change would then be reflected in all the SED Groups whose SED Record
 set contains a reference to that node.  The substrate protocol MUST
 support the ability to Add, Get, and Delete SED Records (refer to
 Section 7 for a generic description of various operations).
 A SED Record object MUST be uniquely identified by attributes as
 defined in the description of "ObjKeyType" in "Generic Object Key
 Type" (Section 5.2.1 of this document).
 The SedRecType object structure is defined as follows:
 <complexType name="SedRecType" abstract="true">
  <complexContent>
   <extension base="sppfb:BasicObjType">
    <sequence>
     <element name="sedName" type="sppfb:ObjNameType"/>
     <element name="sedFunction" type="sppfb:SedFunctionType"
              minOccurs="0"/>
     <element name="isInSvc" type="boolean"/>
     <element name="ttl" type="positiveInteger" minOccurs="0"/>
    </sequence>
   </extension>
  </complexContent>
 </complexType>
 <simpleType name="SedFunctionType">
  <restriction base="token">
   <enumeration value="routing"/>
   <enumeration value="lookup"/>
  </restriction>
 </simpleType>
 The SedRecType object is composed of the following elements:
 o  base: All first-class objects extend BasicObjType (see
    Section 5.1).

Cartwright, et al. Standards Track [Page 29] RFC 7877 SSPF August 2016

 o  sedName: The character string that contains the name of the SED
    Record.  It uniquely identifies this object within the context of
    the Registrant ID (a child element of the base element as
    described above).
 o  sedFunction: As described in [RFC6461], SED falls primarily into
    one of two categories or functions: LUF and LRF.  To remove any
    ambiguity as to the function a SED Record is intended to provide,
    this optional element allows the provisioning party to make its
    intentions explicit.
 o  isInSvc: A boolean element that defines whether or not this SED
    Record is in service.  The session establishment information
    contained in a SED Record that is in service is a candidate for
    inclusion in resolution responses for TNs that are either directly
    associated to this SED Record or for Public Identities residing in
    a Destination Group that is associated to a SED Group, which, in
    turn, has an association to this SED Record.
 o  ttl: Number of seconds that an addressing server may cache a
    particular SED Record.
 As described above, SED Records are based on abstract type
 SedRecType.  The concrete types that use SedRecType as an extension
 base are NAPTRType, NSType, and URIType.  The definitions of these
 types are included below.  The NAPTRType object is comprised of the
 data elements necessary for a Naming Authority Pointer (NAPTR) (see
 [RFC3403]) that contains routing information for a SED Group.  The
 NSType object is comprised of the data elements necessary for a DNS
 name server that points to another DNS server that contains the
 desired routing information.  The NSType is relevant only when the
 resolution protocol is ENUM (see [RFC6116]).  The URIType object is
 comprised of the data elements necessary to house a URI.
 The data provisioned in a Registry can be leveraged for many purposes
 and queried using various protocols including SIP, ENUM, and others.
 As such, the resolution data represented by the SED Records must be
 in a form suitable for transport using one of these protocols.  In
 the NAPTRType, for example, if the URI is associated with a
 Destination Group, the user part of the replacement string <uri> that
 may require the Public Identifier cannot be preset.  As a SIP
 Redirect, the resolution server will apply <ere> pattern on the input
 Public Identifier in the query and process the replacement string by
 substituting any back references in the <uri> to arrive at the final
 URI that is returned in the SIP Contact header.  For an ENUM query,
 the resolution server will simply return the values of the <ere> and
 <uri> members of the URI.

Cartwright, et al. Standards Track [Page 30] RFC 7877 SSPF August 2016

 <complexType name="NAPTRType">
  <complexContent>
   <extension base="sppfb:SedRecType">
    <sequence>
     <element name="order" type="unsignedShort"/>
     <element name="flags" type="sppfb:FlagsType" minOccurs="0"/>
     <element name="svcs" type="sppfb:SvcType"/>
     <element name="regx" type="sppfb:RegexParamType" minOccurs="0"/>
     <element name="repl" type="sppfb:ReplType" minOccurs="0"/>
     <element name="ext" type="sppfb:ExtAnyType" minOccurs="0"/>
    </sequence>
   </extension>
  </complexContent>
 </complexType>
 <complexType name="NSType">
  <complexContent>
   <extension base="sppfb:SedRecType">
    <sequence>
     <element name="hostName" type="token"/>
     <element name="ipAddr" type="sppfb:IPAddrType"
              minOccurs="0" maxOccurs="unbounded"/>
     <element name="ext" type="sppfb:ExtAnyType" minOccurs="0"/>
    </sequence>
   </extension>
  </complexContent>
 </complexType>
 <complexType name="IPAddrType">
  <sequence>
   <element name="addr" type="sppfb:AddrStringType"/>
   <element name="ext" type="sppfb:ExtAnyType" minOccurs="0"/>
  </sequence>
  <attribute name="type" type="sppfb:IPType" default="IPv4"/>
 </complexType>
 <simpleType name="IPType">
  <restriction base="token">
   <enumeration value="IPv4"/>
   <enumeration value="IPv6"/>
  </restriction>
 </simpleType>
 <complexType name="URIType">
  <complexContent>
   <extension base="sppfb:SedRecType">
    <sequence>
     <element name="ere" type="token" default="^(.*)$"/>

Cartwright, et al. Standards Track [Page 31] RFC 7877 SSPF August 2016

     <element name="uri" type="anyURI"/>
     <element name="ext" type="sppfb:ExtAnyType" minOccurs="0"/>
    </sequence>
   </extension>
  </complexContent>
 </complexType>
 <simpleType name="flagsType">
  <restriction base="token">
   <length value="1"/>
   <pattern value="[A-Z]|[a-z]|[0-9]"/>
  </restriction>
 </simpleType>
 The NAPTRType object is composed of the following elements:
 o  order: Order value in an ENUM NAPTR, relative to other NAPTRType
    objects in the same SED Group.
 o  svcs: ENUM service(s) that is served by the SBE.  This field's
    value must be of the form specified in [RFC6116] (e.g.,
    E2U+pstn:sip+sip).  The allowable values are a matter of policy
    and are not limited by this protocol.
 o  regx: NAPTR's regular expression field.  If this is not included,
    then the repl field must be included.
 o  repl: NAPTR replacement field; it should only be provided if the
    regx field is not provided; otherwise, the server will ignore it.
 o  ext: Point of extensibility described in Section 3.3.
 The NSType object is composed of the following elements:
 o  hostName: Root-relative host name of the name server.
 o  ipAddr: Zero or more objects of type IpAddrType.  Each object
    holds an IP Address and the IP Address type ("IPv4" or "IPv6").
 o  ext: Point of extensibility described in Section 3.3.
 The URIType object is composed of the following elements:
 o  ere: The POSIX Extended Regular Expression (ere) as defined in
    [RFC3986].

Cartwright, et al. Standards Track [Page 32] RFC 7877 SSPF August 2016

 o  uri: the URI as defined in [RFC3986].  In some cases, this will
    serve as the replacement string, and it will be left to the
    resolution server to arrive at the final usable URI.

6.5. SED Group Offer

 The list of peer organizations whose resolution responses can include
 the SED contained in a given SED Group is controlled by the
 organization to which a SED Group object belongs (its Registrant) and
 the peer organization that submits resolution requests (a data
 recipient, also known as a peering organization).  The Registrant
 offers access to a SED Group by submitting a SED Group Offer.  The
 data recipient can then accept or reject that offer.  Not until
 access to a SED Group has been offered and accepted will the data
 recipient's organization ID be included in the peeringOrg list in a
 SED Group object, and that SED Group's peering information becomes a
 candidate for inclusion in the responses to the resolution requests
 submitted by that data recipient.  The substrate protocol MUST
 support the ability to Add, Get, Delete, Accept, and Reject SED Group
 Offers (refer to Section 7 for a generic description of various
 operations).
 A SED Group Offer object MUST be uniquely identified by attributes as
 defined in the description of "SedGrpOfferKeyType" in "Derived Object
 Key Types" (Section 5.2.2 of this document).

Cartwright, et al. Standards Track [Page 33] RFC 7877 SSPF August 2016

 The SedGrpOfferType object structure is defined as follows:
 <complexType name="SedGrpOfferType">
  <complexContent>
   <extension base="sppfb:BasicObjType">
    <sequence>
     <element name="sedGrpOfferKey" type="sppfb:SedGrpOfferKeyType"/>
     <element name="status" type="sppfb:SedGrpOfferStatusType"/>
     <element name="offerDateTime" type="dateTime"/>
     <element name="acceptDateTime" type="dateTime" minOccurs="0"/>
     <element name="ext" type="sppfb:ExtAnyType" minOccurs="0"/>
    </sequence>
   </extension>
  </complexContent>
 </complexType>
 <complexType name="SedGrpOfferKeyType" abstract="true">
  <annotation>
   <documentation>
   -- Generic type that represents the key for a SED Group Offer. Must
      be defined in concrete form in a substrate "protocol"
      specification. --
   </documentation>
  </annotation>
 </complexType>
 <simpleType name="SedGrpOfferStatusType">
  <restriction base="token">
   <enumeration value="offered"/>
   <enumeration value="accepted"/>
  </restriction>
 </simpleType>
 The SedGrpOfferType object is composed of the following elements:
 o  base: All first-class objects extend BasicObjType (see
    Section 5.1).
 o  sedGrpOfferKey: The object that identifies the SED that is or has
    been offered and the organization to which it is or has been
    offered.
 o  status: The status of the offer, offered or accepted.  The server
    controls the status.  It is automatically set to "offered"
    whenever a new SED Group Offer is added and is automatically set
    to "accepted" if and when that offer is accepted.  The value of
    the element is ignored when passed in by the client.

Cartwright, et al. Standards Track [Page 34] RFC 7877 SSPF August 2016

 o  offerDateTime: Date and time in UTC when the SED Group Offer was
    added.
 o  acceptDateTime: Date and time in UTC when the SED Group Offer was
    accepted.

6.6. Egress Route

 In a high-availability environment, the originating SSP likely has
 more than one egress path to the ingress SBE of the target SSP.  If
 the originating SSP wants to exercise greater control and choose a
 specific egress SBE to be associated to the target ingress SBE, it
 can do so using the EgrRteType object.
 An Egress Route object MUST be uniquely identified by attributes as
 defined in the description of "ObjKeyType" in "Generic Object Key
 Type" (Section 5.2.1 of this document).
 Assume that the target SSP has offered, as part of its SED, to share
 one or more Ingress Routes and that the originating SSP has accepted
 the offer.  In order to add the Egress Route to the Registry, the
 originating SSP uses a valid regular expression to rewrite the
 Ingress Route in order to include the egress SBE information.  Also,
 more than one Egress Route can be associated with a given Ingress
 Route in support of fault-tolerant configurations.  The supporting
 SPPF structure provides a way to include route precedence information
 to help manage traffic to more than one outbound egress SBE.
 The substrate protocol MUST support the ability to Add, Get, and
 Delete Egress Routes (refer to Section 7 for a generic description of
 various operations).  The EgrRteType object structure is defined as
 follows:
 <complexType name="EgrRteType">
  <complexContent>
   <extension base="sppfb:BasicObjType">
    <sequence>
     <element name="egrRteName" type="sppfb:ObjNameType"/>
     <element name="pref" type="unsignedShort"/>
     <element name="regxRewriteRule" type="sppfb:RegexParamType"/>
     <element name="ingrSedGrp" type="sppfb:ObjKeyType"
              minOccurs="0" maxOccurs="unbounded"/>
     <element name="svcs" type="sppfb:SvcType" minOccurs="0"/>
     <element name="ext" type="sppfb:ExtAnyType" minOccurs="0"/>
    </sequence>
   </extension>
  </complexContent>
 </complexType>

Cartwright, et al. Standards Track [Page 35] RFC 7877 SSPF August 2016

 The EgrRteType object is composed of the following elements:
 o  base: All first-class objects extend BasicObjType (see
    Section 5.1).
 o  egrRteName: The name of the Egress Route.
 o  pref: The preference of this Egress Route relative to other Egress
    Routes that may get selected when responding to a resolution
    request.
 o  regxRewriteRule: The regular expression rewrite rule that should
    be applied to the regular expression of the ingress NAPTR(s) that
    belongs to the Ingress Route.
 o  ingrSedGrp: The ingress SED Group that the Egress Route should be
    used for.
 o  svcs: ENUM service(s) that is served by an Egress Route.  This
    element is used to identify the ingress NAPTRs associated with the
    SED Group to which an Egress Route's regxRewriteRule should be
    applied.  If no ENUM service(s) is associated with an Egress
    Route, then the Egress Route's regxRewriteRule should be applied
    to all the NAPTRs associated with the SED Group.  This field's
    value must be of the form specified in [RFC6116] (e.g.,
    E2U+pstn:sip+sip).  The allowable values are a matter of policy
    and are not limited by this protocol.
 o  ext: Point of extensibility described in Section 3.3.

7. Framework Operations

 In addition to the operation-specific object types, all operations
 MAY specify the minor version of the protocol that when used in
 conjunction with the major version (which can be, for instance,
 specified in the protocol Namespace) can serve to identify the
 version of the SPPF protocol that the client is using.  If the minor
 version is not specified, the latest minor version supported by the
 SPPF server for the given major version will be used.  Additionally,
 operations that may potentially modify persistent protocol objects
 SHOULD include a transaction ID as well.

Cartwright, et al. Standards Track [Page 36] RFC 7877 SSPF August 2016

7.1. Add Operation

 Any conforming substrate "protocol" specification MUST provide a
 definition for the operation that adds one or more SPPF objects into
 the Registry.  If the object, as identified by the request attributes
 that form part of the object's key, does not exist, then the Registry
 MUST create the object.  If the object does exist, then the Registry
 MUST replace the current properties of the object with the properties
 passed in as part of the Add operation.
 Note that this effectively allows modification of a preexisting
 object.
 If the entity that issued the command is not authorized to perform
 this operation, an appropriate error message MUST be returned from
 amongst the response messages defined in "Response Message Types"
 (Section 5.3 of this document).

7.2. Delete Operation

 Any conforming substrate "protocol" specification MUST provide a
 definition for the operation that deletes one or more SPPF objects
 from the Registry using the object's key.
 If the entity that issued the command is not authorized to perform
 this operation, an appropriate error message MUST be returned from
 amongst the response messages defined in "Response Message Types"
 (Section 5.3 of this document).
 When an object is deleted, any references to that object must of
 course also be removed as the SPPF server implementation fulfills the
 deletion request.  Furthermore, the deletion of a composite object
 must also result in the deletion of the objects it contains.  As a
 result, the following rules apply to the deletion of SPPF object
 types:
 o  Destination Groups: When a Destination Group is deleted, any
    cross-references between that destination group and any SED Group
    must be automatically removed by the SPPF implementation as part
    of fulfilling the deletion request.  Similarly, any cross-
    references between that Destination Group and any Public
    Identifier must be removed by the SPPF implementation.
 o  SED Groups: When a SED Group is deleted, any references between
    that SED Group and any Destination Group must be automatically
    removed by the SPPF implementation as part of fulfilling the
    deletion request.  Similarly, any cross-references between that
    SED Group and any SED Records must be removed by the SPPF

Cartwright, et al. Standards Track [Page 37] RFC 7877 SSPF August 2016

    implementation as part of fulfilling the deletion request.
    Furthermore, SED Group Offers relating to that SED Group must also
    be deleted.
 o  SED Records: When a SED Record is deleted, any cross-references
    between that SED Record and any SED Group must be removed by the
    SPPF implementation as part of fulfilling the deletion request.
    Similarly, any reference between that SED Record and any Public
    Identifier must be removed by the SPPF implementation.
 o  Public Identifiers: When a Public Identifier is deleted, any
    cross-references between that Public Identifier and any referenced
    Destination Group must be removed by the SPPF implementation as
    part of fulfilling the deletion request.  Any references to SED
    Records associated directly to that Public Identifier must also be
    deleted by the SPPF implementation.
 Deletes MUST be atomic.

7.3. Get Operations

 At times, on behalf of the Registrant, the Registrar may need to get
 information about SPPF objects that were previously provisioned in
 the Registry.  A few examples include logging, auditing, and pre-
 provisioning dependency checking.  This query mechanism is limited to
 aid provisioning scenarios and should not be confused with query
 protocols provided as part of the resolution system (e.g., ENUM and
 SIP).
 Any conforming "protocol" specification MUST provide a definition for
 the operation that queries the details of one or more SPPF objects
 from the Registry using the object's key.  If the entity that issued
 the command is not authorized to perform this operation, an
 appropriate error message MUST be returned from among the response
 messages defined in Section 5.3.
 If the response to the Get operation includes an object(s) that
 extends the BasicObjType, the Registry MUST include the "cDate" and
 "mDate", if applicable.

7.4. Accept Operations

 In SPPF, a SED Group Offer can be accepted or rejected by, or on
 behalf of, the Registrant to which the SED Group has been offered
 (refer to Section 6.5 of this document for a description of the SED
 Group Offer object).  The Accept operation is used to accept the SED
 Group Offers.  Any conforming substrate "protocol" specification MUST
 provide a definition for the operation to accept SED Group Offers by,

Cartwright, et al. Standards Track [Page 38] RFC 7877 SSPF August 2016

 or on behalf of, the Registrant, using the SED Group Offer object
 key.
 Not until access to a SED Group has been offered and accepted will
 the Registrant's organization ID be included in the peeringOrg list
 in that SED Group object, and that SED Group's peering information
 becomes a candidate for inclusion in the responses to the resolution
 requests submitted by that Registrant.  A SED Group Offer that is in
 the "offered" status is accepted by, or on behalf of, the Registrant
 to which it has been offered.  When the SED Group Offer is accepted,
 the SED Group Offer is moved to the "accepted" status and the data
 recipient's organization ID is added into the list of peerOrgIds for
 that SED Group.
 If the entity that issued the command is not authorized to perform
 this operation, an appropriate error message MUST be returned from
 amongst the response messages defined in "Response Message Types"
 (Section 5.3 of this document).

7.5. Reject Operations

 In SPPF, a SED Group Offer object can be accepted or rejected by, or
 on behalf of, the Registrant to which the SED Group has been offered
 (refer to "Framework Data Model Objects", Section 6 of this document,
 for a description of the SED Group Offer object).  Furthermore, that
 offer may be rejected, regardless of whether or not it has been
 previously accepted.  The Reject operation is used to reject the SED
 Group Offer.  When the SED Group Offer is rejected, that SED Group
 Offer is deleted, and, if appropriate, the data recipient's
 organization ID is removed from the list of peeringOrg IDs for that
 SED Group.  Any conforming substrate "protocol" specification MUST
 provide a definition for the operation to reject SED Group Offers by,
 or on behalf of, the Registrant, using the SED Group Offer object
 key.
 If the entity that issued the command is not authorized to perform
 this operation, an appropriate error message MUST be returned from
 among the response messages defined in "Response Message Types"
 (Section 5.3 of this document).

7.6. Get Server Details Operation

 In SPPF, the Get Server Details operation can be used to request
 certain details about the SPPF server that include the SPPF server's
 current status and the major/minor version of the SPPF protocol
 supported by the SPPF server.

Cartwright, et al. Standards Track [Page 39] RFC 7877 SSPF August 2016

 Any conforming substrate "protocol" specification MUST provide a
 definition for the operation to request such details from the SPPF
 server.  If the entity that issued the command is not authorized to
 perform this operation, an appropriate error message MUST be returned
 from among the response messages defined in "Response Message Types"
 (Section 5.3 of this document).

8. XML Considerations

 XML serves as the encoding format for SPPF, allowing complex
 hierarchical data to be expressed in a text format that can be read,
 saved, and manipulated with both traditional text tools and tools
 specific to XML.
 XML is case sensitive.  Unless stated otherwise, the character casing
 of XML specifications in this document MUST be preserved to develop a
 conforming specification.
 This section discusses a small number of XML-related considerations
 pertaining to SPPF.

8.1. Namespaces

 All SPPF elements are defined in the Namespaces in the "IANA
 Considerations" and "Formal Framework Specification" sections of this
 document.

8.2. Versioning and Character Encoding

 All XML instances SHOULD begin with an <?xml?> declaration to
 identify the version of XML that is being used, optionally identify
 use of the character encoding used, and optionally provide a hint to
 an XML parser that an external schema file is needed to validate the
 XML instance.
 Conformant XML parsers recognize both UTF-8 (defined in [RFC3629])
 and UTF-16 (defined in [RFC2781]); per [RFC2277], UTF-8 is the
 RECOMMENDED character encoding for use with SPPF.
 Character encodings other than UTF-8 and UTF-16 are allowed by XML.
 UTF-8 is the default encoding assumed by XML in the absence of an
 "encoding" attribute or a byte order mark (BOM); thus, the "encoding"
 attribute in the XML declaration is OPTIONAL if UTF-8 encoding is
 used.  SPPF clients and servers MUST accept a UTF-8 BOM if present,
 though emitting a UTF-8 BOM is NOT RECOMMENDED.

Cartwright, et al. Standards Track [Page 40] RFC 7877 SSPF August 2016

 Example XML declarations:
 <?xml version="1.0" encoding="UTF-8" standalone="no"?>

9. Security Considerations

 Many SPPF implementations manage data that is considered confidential
 and critical.  Furthermore, SPPF implementations can support
 provisioning activities for multiple Registrars and Registrants.  As
 a result, any SPPF implementation must address the requirements for
 confidentiality, authentication, and authorization.

9.1. Confidentiality and Authentication

 With respect to confidentiality and authentication, the substrate
 protocol requirements section of this document contains security
 properties that the substrate protocol must provide, so that
 authenticated endpoints can exchange data confidentially and with
 integrity protection.  Refer to Section 4 of this document and
 [RFC7878] for the specific solutions to authentication and
 confidentiality.

9.2. Authorization

 With respect to authorization, the SPPF server implementation must
 define and implement a set of authorization rules that precisely
 address (1) which Registrars will be authorized to create/modify/
 delete each SPPF object type for a given Registrant(s) and (2) which
 Registrars will be authorized to view/get each SPPF object type for a
 given Registrant(s).  These authorization rules are a matter of
 policy and are not specified within the context of SPPF.  However,
 any SPPF implementation must specify these authorization rules in
 order to function in a reliable and safe manner.

9.3. Denial of Service

 In general, guidance on Denial-of-Service (DoS) issues is given in
 "Internet Denial of Service Considerations" [RFC4732], which also
 gives a general vocabulary for describing the DoS issue.
 SPPF is a high-level client-server protocol that can be implemented
 on lower-level mechanisms such as remote procedure call and web-
 service API protocols.  As such, it inherits any Denial-of-Service
 issues inherent to the specific lower-level mechanism used for any
 implementation of SPPF.  SPPF also has its own set of higher-level
 exposures that are likely to be independent of lower-layer mechanism
 choices.

Cartwright, et al. Standards Track [Page 41] RFC 7877 SSPF August 2016

9.3.1. DoS Issues Inherited from the Substrate Mechanism

 In general, an SPPF implementation is dependent on the selection and
 implementation of a lower-level substrate protocol and a binding
 between that protocol and SPPF.  The archetypal SPPF implementation
 uses XML [W3C.REC-xml-20081126] representation in a SOAP [SOAPREF]
 request/response framework over HTTP [RFC7230], probably also uses
 Transport Layer Security (TLS) [RFC5246] for on-the-wire data
 integrity and participant authentication, and might use HTTP Digest
 authentication [RFC2069].
 The typical deployment scenario for SPPF is to have servers in a
 managed facility; therefore, techniques such as Network Ingress
 Filtering [RFC2827] are generally applicable.  In short, any DoS
 mechanism affecting a typical HTTP implementation would affect such
 an SPPF implementation; therefore, the mitigation tools for HTTP in
 general also apply to SPPF.
 SPPF does not directly specify an authentication mechanism; instead,
 it relies on the lower-level substrate protocol to provide for
 authentication.  In general, authentication is an expensive
 operation, and one apparent attack vector is to flood an SPPF server
 with repeated requests for authentication, thereby exhausting its
 resources.  Therefore, SPPF implementations SHOULD be prepared to
 handle authentication floods, perhaps by noting repeated failed login
 requests from a given source address and blocking that source
 address.

9.3.2. DoS Issues Specific to SPPF

 The primary defense mechanism against DoS within SPPF is
 authentication.  Implementations MUST tightly control access to the
 SPPF service, SHOULD implement DoS and other policy control
 screening, and MAY employ a variety of policy violation reporting and
 response measures such as automatic blocking of specific users and
 alerting of operations personnel.  In short, the primary SPPF
 response to DoS-like activity by a user is to block that user or
 subject their actions to additional review.
 SPPF allows a client to submit multiple-element or "batch" requests
 that may insert or otherwise affect a large amount of data with a
 single request.  In the simplest case, the server progresses
 sequentially through each element in a batch, completing one before
 starting the next.  Mid-batch failures are handled by stopping the
 batch and rolling back the data store to its pre-request state.  This
 "stop and roll back" design provides a DoS opportunity.  A hostile
 client could repeatedly issue large batch requests with one or more
 failing elements, causing the server to repeatedly stop and roll back

Cartwright, et al. Standards Track [Page 42] RFC 7877 SSPF August 2016

 large transactions.  The suggested response is to monitor clients for
 such failures and take administrative action (such as blocking the
 user) when an excessive number of rollbacks is reported.
 An additional suggested response is for an implementer to set their
 maximum allowable XML message size and their maximum allowable batch
 size at a level that they feel protects their operational instance,
 given the hardware sizing they have in place and the expected load
 and size needs that their users expect.

9.4. Information Disclosure

 It is not uncommon for the logging systems to document on-the-wire
 messages for various purposes, such as debugging, auditing, and
 tracking.  At the minimum, the various support and administration
 staff will have access to these logs.  Also, if an unprivileged user
 gains access to the SPPF deployments and/or support systems, it will
 have access to the information that is potentially deemed
 confidential.  To manage information disclosure concerns beyond the
 substrate level, SPPF implementations MAY provide support for
 encryption at the SPPF object level.

9.5. Non-repudiation

 In some situations, it may be required to protect against denial of
 involvement (see [RFC4949]) and tackle non-repudiation concerns in
 regard to SPPF messages.  This type of protection is useful to
 satisfy authenticity concerns related to SPPF messages beyond the
 end-to-end connection integrity, confidentiality, and authentication
 protection that the substrate layer provides.  This is an optional
 feature, and some SPPF implementations MAY provide support for it.

9.6. Replay Attacks

 Anti-replay protection ensures that a given SPPF object replayed at a
 later time won't affect the integrity of the system.  SPPF provides
 at least one mechanism to fight against replay attacks.  Use of the
 optional client transaction identifier allows the SPPF client to
 correlate the request message with the response and to be sure that
 it is not a replay of a server response from earlier exchanges.  Use
 of unique values for the client transaction identifier is highly
 encouraged to avoid chance matches to a potential replay message.

Cartwright, et al. Standards Track [Page 43] RFC 7877 SSPF August 2016

9.7. Compromised or Malicious Intermediary

 The SPPF client or Registrar can be a separate entity acting on
 behalf of the Registrant in facilitating provisioning transactions to
 the Registry.  Therefore, even though the substrate layer provides
 end-to-end protection for each specific SPPP connection between
 client and server, data might be available in clear text before or
 after it traverses an SPPP connection.  Therefore, a
 man-in-the-middle attack by one of the intermediaries is a
 possibility that could affect the integrity of the data that belongs
 to the Registrant and/or expose peering data to unintended actors.

10. Internationalization Considerations

 Character encodings to be used for SPPF elements are described in
 Section 8.2.  The use of time elements in the protocol is specified
 in Section 3.2.  Where human-readable messages that are presented to
 an end user are used in the protocol, those messages SHOULD be tagged
 according to [RFC5646], and the substrate protocol MUST support a
 respective mechanism to transmit such tags together with those human-
 readable messages.

11. IANA Considerations

11.1. URN Assignments

 This document uses URNs to describe XML Namespaces and XML Schemas
 conforming to a Registry mechanism described in [RFC3688].
 Two URI assignments have been made:
 Registration for the SPPF XML Namespace:
 urn:ietf:params:xml:ns:sppf:base:1
 Registrant Contact: The IESG
 XML: None.  Namespace URIs do not represent an XML specification.
 Registration request for the XML Schema:
 URI: urn:ietf:params:xml:schema:sppf:1
 Registrant Contact: IESG
 XML: See "Formal Specification" (Section 12 of this document).

Cartwright, et al. Standards Track [Page 44] RFC 7877 SSPF August 2016

11.2. Organization Identifier Namespace Registry

 IANA has created and will maintain a registry titled "SPPF OrgIdType
 Namespaces".  The formal syntax is described in Section 5.1.
 Assignments consist of the OrgIdType Namespace string and the
 definition of the associated Namespace.  This document makes the
 following initial assignment for the OrgIdType Namespaces:
       OrgIdType Namespace string                       Namespace
       --------------------------                       ---------
       IANA Enterprise Numbers                          iana-en
 Future assignments are to be made through the well-known IANA Policy
 "RFC Required" (see Section 4.1 of [RFC5226]).  Such assignments will
 typically be requested when a new Namespace for identification of SPs
 is defined.

12. Formal Specification

 This section provides the XSD for the SPPF protocol.
 <?xml version="1.0" encoding="UTF-8"?>
 <schema xmlns:sppfb="urn:ietf:params:xml:ns:sppf:base:1"
 xmlns="http://www.w3.org/2001/XMLSchema"
 targetNamespace="urn:ietf:params:xml:ns:sppf:base:1"
 elementFormDefault="qualified" xml:lang="EN">
  <annotation>
   <documentation>
    ---- Generic object key types to be defined by specific
         substrate/architecture.  The types defined here can
         be extended by the specific architecture to
         define the Object Identifiers. ----
   </documentation>
  </annotation>
  <complexType name="ObjKeyType"
   abstract="true">
   <annotation>
    <documentation>
     ---- Generic type that represents the
          key for various objects in SPPF. ----
    </documentation>
   </annotation>
  </complexType>

Cartwright, et al. Standards Track [Page 45] RFC 7877 SSPF August 2016

  <complexType name="SedGrpOfferKeyType" abstract="true">
   <complexContent>
    <extension base="sppfb:ObjKeyType">
     <annotation>
      <documentation>
      ---- Generic type that represents
           the key for a SED Group Offer. ----
      </documentation>
     </annotation>
    </extension>
   </complexContent>
  </complexType>
  <complexType name="PubIdKeyType" abstract="true">
   <complexContent>
    <extension base="sppfb:ObjKeyType">
     <annotation>
      <documentation>
       ----Generic type that
       represents the key
       for a Pub ID. ----
      </documentation>
     </annotation>
    </extension>
   </complexContent>
  </complexType>
  <annotation>
   <documentation>
     ---- Object Type Definitions ----
   </documentation>
  </annotation>
  <complexType name="SedGrpType">
   <complexContent>
    <extension base="sppfb:BasicObjType">
     <sequence>
      <element name="sedGrpName" type="sppfb:ObjNameType"/>
      <element name="sedRecRef" type="sppfb:SedRecRefType"
               minOccurs="0" maxOccurs="unbounded"/>
      <element name="dgName" type="sppfb:ObjNameType"
               minOccurs="0" maxOccurs="unbounded"/>
      <element name="peeringOrg" type="sppfb:OrgIdType"
               minOccurs="0" maxOccurs="unbounded"/>
      <element name="sourceIdent" type="sppfb:SourceIdentType"
               minOccurs="0" maxOccurs="unbounded"/>
      <element name="isInSvc" type="boolean"/>
      <element name="priority" type="unsignedShort"/>

Cartwright, et al. Standards Track [Page 46] RFC 7877 SSPF August 2016

      <element name="ext"
      type="sppfb:ExtAnyType" minOccurs="0"/>
     </sequence>
    </extension>
   </complexContent>
  </complexType>
  <complexType name="DestGrpType">
   <complexContent>
    <extension base="sppfb:BasicObjType">
     <sequence>
      <element name="dgName"
      type="sppfb:ObjNameType"/>
     </sequence>
    </extension>
   </complexContent>
  </complexType>
  <complexType name="PubIdType" abstract="true">
   <complexContent>
    <extension base="sppfb:BasicObjType">
     <sequence>
      <element name="dgName" type="sppfb:ObjNameType"
               minOccurs="0" maxOccurs="unbounded"/>
     </sequence>
    </extension>
   </complexContent>
  </complexType>
  <complexType name="TNType">
   <complexContent>
    <extension base="sppfb:PubIdType">
     <sequence>
      <element name="tn" type="sppfb:NumberValType"/>
      <element name="corInfo" type="sppfb:CORInfoType" minOccurs="0"/>
      <element name="sedRecRef" type="sppfb:SedRecRefType"
               minOccurs="0" maxOccurs="unbounded"/>
     </sequence>
    </extension>
   </complexContent>
  </complexType>
  <complexType name="TNRType">
   <complexContent>
    <extension base="sppfb:PubIdType">
     <sequence>
      <element name="range" type="sppfb:NumberRangeType"/>
      <element name="corInfo" type="sppfb:CORInfoType" minOccurs="0"/>
     </sequence>
    </extension>
   </complexContent>
  </complexType>

Cartwright, et al. Standards Track [Page 47] RFC 7877 SSPF August 2016

  <complexType name="TNPType">
   <complexContent>
    <extension base="sppfb:PubIdType">
     <sequence>
      <element name="tnPrefix" type="sppfb:NumberValType"/>
      <element name="corInfo" type="sppfb:CORInfoType" minOccurs="0"/>
     </sequence>
    </extension>
   </complexContent>
  </complexType>
  <complexType name="RNType">
   <complexContent>
    <extension base="sppfb:PubIdType">
     <sequence>
      <element name="rn" type="sppfb:NumberValType"/>
      <element name="corInfo" type="sppfb:CORInfoType" minOccurs="0"/>
     </sequence>
    </extension>
   </complexContent>
  </complexType>
   <complexType name="URIPubIdType">
   <complexContent>
    <extension base="sppfb:PubIdType">
     <sequence>
      <element name="uri" type="anyURI"/>
      <element name="ext" type="sppfb:ExtAnyType" minOccurs="0"/>
     </sequence>
    </extension>
   </complexContent>
  </complexType>
  <complexType name="SedRecType" abstract="true">
   <complexContent>
    <extension base="sppfb:BasicObjType">
     <sequence>
      <element name="sedName" type="sppfb:ObjNameType"/>
      <element name="sedFunction" type="sppfb:SedFunctionType"
               minOccurs="0"/>
      <element name="isInSvc" type="boolean"/>
      <element name="ttl" type="positiveInteger" minOccurs="0"/>
     </sequence>
    </extension>
   </complexContent>
  </complexType>
  <complexType name="NAPTRType">
   <complexContent>
    <extension base="sppfb:SedRecType">
     <sequence>
      <element name="order" type="unsignedShort"/>

Cartwright, et al. Standards Track [Page 48] RFC 7877 SSPF August 2016

      <element name="flags" type="sppfb:FlagsType" minOccurs="0"/>
      <element name="svcs" type="sppfb:SvcType"/>
      <element name="regx" type="sppfb:RegexParamType" minOccurs="0"/>
      <element name="repl" type="sppfb:ReplType" minOccurs="0"/>
      <element name="ext" type="sppfb:ExtAnyType" minOccurs="0"/>
     </sequence>
    </extension>
   </complexContent>
  </complexType>
  <complexType name="NSType">
   <complexContent>
    <extension base="sppfb:SedRecType">
     <sequence>
      <element name="hostName" type="token"/>
      <element name="ipAddr" type="sppfb:IPAddrType"
               minOccurs="0" maxOccurs="unbounded"/>
      <element name="ext" type="sppfb:ExtAnyType" minOccurs="0"/>
     </sequence>
    </extension>
   </complexContent>
  </complexType>
  <complexType name="URIType">
   <complexContent>
    <extension base="sppfb:SedRecType">
     <sequence>
      <element name="ere" type="token" default="^(.*)$"/>
      <element name="uri" type="anyURI"/>
      <element name="ext" type="sppfb:ExtAnyType" minOccurs="0"/>
     </sequence>
    </extension>
   </complexContent>
  </complexType>
  <complexType name="SedGrpOfferType">
   <complexContent>
    <extension base="sppfb:BasicObjType">
     <sequence>
      <element name="sedGrpOfferKey" type="sppfb:SedGrpOfferKeyType"/>
      <element name="status" type="sppfb:SedGrpOfferStatusType"/>
      <element name="offerDateTime" type="dateTime"/>
      <element name="acceptDateTime" type="dateTime" minOccurs="0"/>
      <element name="ext" type="sppfb:ExtAnyType" minOccurs="0"/>
     </sequence>
    </extension>
   </complexContent>
  </complexType>
  <complexType name="EgrRteType">
   <complexContent>
    <extension base="sppfb:BasicObjType">

Cartwright, et al. Standards Track [Page 49] RFC 7877 SSPF August 2016

     <sequence>
      <element name="egrRteName" type="sppfb:ObjNameType"/>
      <element name="pref" type="unsignedShort"/>
      <element name="regxRewriteRule" type="sppfb:RegexParamType"/>
      <element name="ingrSedGrp" type="sppfb:ObjKeyType"
               minOccurs="0" maxOccurs="unbounded"/>
      <element name="svcs" type="sppfb:SvcType" minOccurs="0"/>
      <element name="ext" type="sppfb:ExtAnyType" minOccurs="0"/>
     </sequence>
    </extension>
   </complexContent>
  </complexType>
  <annotation>
   <documentation>
    ---- Abstract Object and Element Type Definitions ----
   </documentation>
  </annotation>
  <complexType name="BasicObjType" abstract="true">
   <sequence>
    <element name="rant" type="sppfb:OrgIdType"/>
    <element name="rar" type="sppfb:OrgIdType"/>
    <element name="cDate" type="dateTime" minOccurs="0"/>
    <element name="mDate" type="dateTime" minOccurs="0"/>
    <element name="ext" type="sppfb:ExtAnyType" minOccurs="0"/>
   </sequence>
  </complexType>
  <complexType name="RegexParamType">
   <sequence>
    <element name="ere" type="sppfb:RegexType" default="^(.*)$"/>
    <element name="repl" type="sppfb:ReplType"/>
   </sequence>
  </complexType>
  <complexType name="IPAddrType">
   <sequence>
    <element name="addr" type="sppfb:AddrStringType"/>
    <element name="ext" type="sppfb:ExtAnyType" minOccurs="0"/>
   </sequence>
   <attribute name="type" type="sppfb:IPType" default="v4"/>
  </complexType>
  <complexType name="SedRecRefType">
   <sequence>
    <element name="sedKey" type="sppfb:ObjKeyType"/>
    <element name="priority" type="unsignedShort"/>
    <element name="ext" type="sppfb:ExtAnyType" minOccurs="0"/>
   </sequence>
  </complexType>
  <complexType name="SourceIdentType">
   <sequence>

Cartwright, et al. Standards Track [Page 50] RFC 7877 SSPF August 2016

    <element name="sourceIdentRegex" type="sppfb:RegexType"/>
    <element name="sourceIdentScheme"
             type="sppfb:SourceIdentSchemeType"/>
    <element name="ext" type="sppfb:ExtAnyType" minOccurs="0"/>
   </sequence>
  </complexType>
  <complexType name="CORInfoType">
   <sequence>
    <element name="corClaim" type="boolean" default="true"/>
    <element name="cor" type="boolean" default="false" minOccurs="0"/>
    <element name="corDate" type="dateTime" minOccurs="0"/>
   </sequence>
  </complexType>
  <complexType name="SvcMenuType">
   <sequence>
    <element name="serverStatus" type="sppfb:ServerStatusType"/>
    <element name="majMinVersion" type="token" maxOccurs="unbounded"/>
    <element name="objURI" type="anyURI" maxOccurs="unbounded"/>
    <element name="extURI" type="anyURI"
             minOccurs="0" maxOccurs="unbounded"/>
   </sequence>
  </complexType>
  <complexType name="ExtAnyType">
   <sequence>
    <any namespace="##other" maxOccurs="unbounded"/>
   </sequence>
  </complexType>
  <simpleType name="FlagsType">
   <restriction base="token">
    <length value="1"/>
    <pattern value="[A-Z]|[a-z]|[0-9]"/>
   </restriction>
  </simpleType>
  <simpleType name="SvcType">
   <restriction base="token">
    <minLength value="1"/>
   </restriction>
  </simpleType>
  <simpleType name="RegexType">
   <restriction base="token">
    <minLength value="1"/>
   </restriction>
  </simpleType>
  <simpleType name="ReplType">
   <restriction base="token">
    <minLength value="1"/>
    <maxLength value="255"/>
   </restriction>

Cartwright, et al. Standards Track [Page 51] RFC 7877 SSPF August 2016

  </simpleType>
  <simpleType name="OrgIdType">
   <restriction base="token"/>
  </simpleType>
  <simpleType name="ObjNameType">
   <restriction base="token">
    <minLength value="3"/>
    <maxLength value="80"/>
   </restriction>
  </simpleType>
  <simpleType name="TransIdType">
   <restriction base="token">
    <minLength value="3"/>
    <maxLength value="120"/>
   </restriction>
  </simpleType>
  <simpleType name="MinorVerType">
   <restriction base="unsignedLong"/>
  </simpleType>
  <simpleType name="AddrStringType">
   <restriction base="token">
    <minLength value="3"/>
    <maxLength value="45"/>
   </restriction>
  </simpleType>
  <simpleType name="IPType">
   <restriction base="token">
    <enumeration value="v4"/>
    <enumeration value="v6"/>
   </restriction>
  </simpleType>
  <simpleType name="SourceIdentSchemeType">
   <restriction base="token">
    <enumeration value="uri"/>
    <enumeration value="ip"/>
    <enumeration value="rootDomain"/>
   </restriction>
  </simpleType>
  <simpleType name="ServerStatusType">
   <restriction base="token">
    <enumeration value="inService"/>
    <enumeration value="outOfService"/>
   </restriction>
  </simpleType>
  <simpleType name="SedGrpOfferStatusType">
   <restriction base="token">
    <enumeration value="offered"/>
    <enumeration value="accepted"/>

Cartwright, et al. Standards Track [Page 52] RFC 7877 SSPF August 2016

   </restriction>
  </simpleType>
  <simpleType name="NumberValType">
   <restriction base="token">
    <maxLength value="20"/>
    <pattern value="\+?\d\d*"/>
   </restriction>
  </simpleType>
  <simpleType name="NumberTypeEnum">
   <restriction base="token">
    <enumeration value="TN"/>
    <enumeration value="TNPrefix"/>
    <enumeration value="RN"/>
   </restriction>
  </simpleType>
  <simpleType name="SedFunctionType">
   <restriction base="token">
    <enumeration value="routing"/>
    <enumeration value="lookup"/>
   </restriction>
  </simpleType>
  <complexType name="NumberType">
   <sequence>
    <element name="value" type="sppfb:NumberValType"/>
    <element name="type" type="sppfb:NumberTypeEnum"/>
   </sequence>
  </complexType>
  <complexType name="NumberRangeType">
   <sequence>
    <element name="startRange" type="sppfb:NumberValType"/>
    <element name="endRange" type="sppfb:NumberValType"/>
   </sequence>
  </complexType>
 </schema>

Cartwright, et al. Standards Track [Page 53] RFC 7877 SSPF August 2016

13. References

13.1. Normative References

 [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
            Requirement Levels", BCP 14, RFC 2119,
            DOI 10.17487/RFC2119, March 1997,
            <http://www.rfc-editor.org/info/rfc2119>.
 [RFC2277]  Alvestrand, H., "IETF Policy on Character Sets and
            Languages", BCP 18, RFC 2277, DOI 10.17487/RFC2277,
            January 1998, <http://www.rfc-editor.org/info/rfc2277>.
 [RFC3629]  Yergeau, F., "UTF-8, a transformation format of ISO
            10646", STD 63, RFC 3629, DOI 10.17487/RFC3629, November
            2003, <http://www.rfc-editor.org/info/rfc3629>.
 [RFC3688]  Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
            DOI 10.17487/RFC3688, January 2004,
            <http://www.rfc-editor.org/info/rfc3688>.
 [RFC3986]  Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
            Resource Identifier (URI): Generic Syntax", STD 66,
            RFC 3986, DOI 10.17487/RFC3986, January 2005,
            <http://www.rfc-editor.org/info/rfc3986>.
 [RFC5226]  Narten, T. and H. Alvestrand, "Guidelines for Writing an
            IANA Considerations Section in RFCs", BCP 26, RFC 5226,
            DOI 10.17487/RFC5226, May 2008,
            <http://www.rfc-editor.org/info/rfc5226>.
 [RFC5234]  Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax
            Specifications: ABNF", STD 68, RFC 5234,
            DOI 10.17487/RFC5234, January 2008,
            <http://www.rfc-editor.org/info/rfc5234>.
 [RFC7878]  Cartwright, K., Bhatia, V., Mule, J., and A. Mayrhofer,
            "Session Peering Provisioning (SPP) Protocol over SOAP",
            RFC 7878, DOI 10.17487/RFC7878, August 2016,
            <http://www.rfc-editor.org/info/rfc7878>.
 [W3C.REC-xml-20081126]
            Bray, T., Paoli, J., Sperberg-McQueen, C., Maler, E., and
            F. Yergeau, "Extensible Markup Language (XML) 1.0 (Fifth
            Edition)", World Wide Web Consortium Recommendation REC-
            xml-20081126, November 2008,
            <http://www.w3.org/TR/2008/REC-xml-20081126>.

Cartwright, et al. Standards Track [Page 54] RFC 7877 SSPF August 2016

13.2. Informative References

 [RFC2069]  Franks, J., Hallam-Baker, P., Hostetler, J., Leach, P.,
            Luotonen, A., Sink, E., and L. Stewart, "An Extension to
            HTTP : Digest Access Authentication", RFC 2069,
            DOI 10.17487/RFC2069, January 1997,
            <http://www.rfc-editor.org/info/rfc2069>.
 [RFC2781]  Hoffman, P. and F. Yergeau, "UTF-16, an encoding of ISO
            10646", RFC 2781, DOI 10.17487/RFC2781, February 2000,
            <http://www.rfc-editor.org/info/rfc2781>.
 [RFC2827]  Ferguson, P. and D. Senie, "Network Ingress Filtering:
            Defeating Denial of Service Attacks which employ IP Source
            Address Spoofing", BCP 38, RFC 2827, DOI 10.17487/RFC2827,
            May 2000, <http://www.rfc-editor.org/info/rfc2827>.
 [RFC3261]  Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston,
            A., Peterson, J., Sparks, R., Handley, M., and E.
            Schooler, "SIP: Session Initiation Protocol", RFC 3261,
            DOI 10.17487/RFC3261, June 2002,
            <http://www.rfc-editor.org/info/rfc3261>.
 [RFC3403]  Mealling, M., "Dynamic Delegation Discovery System (DDDS)
            Part Three: The Domain Name System (DNS) Database",
            RFC 3403, DOI 10.17487/RFC3403, October 2002,
            <http://www.rfc-editor.org/info/rfc3403>.
 [RFC4725]  Mayrhofer, A. and B. Hoeneisen, "ENUM Validation
            Architecture", RFC 4725, DOI 10.17487/RFC4725, November
            2006, <http://www.rfc-editor.org/info/rfc4725>.
 [RFC4732]  Handley, M., Ed., Rescorla, E., Ed., and IAB, "Internet
            Denial-of-Service Considerations", RFC 4732,
            DOI 10.17487/RFC4732, December 2006,
            <http://www.rfc-editor.org/info/rfc4732>.
 [RFC4949]  Shirey, R., "Internet Security Glossary, Version 2",
            FYI 36, RFC 4949, DOI 10.17487/RFC4949, August 2007,
            <http://www.rfc-editor.org/info/rfc4949>.
 [RFC5067]  Lind, S. and P. Pfautz, "Infrastructure ENUM
            Requirements", RFC 5067, DOI 10.17487/RFC5067, November
            2007, <http://www.rfc-editor.org/info/rfc5067>.

Cartwright, et al. Standards Track [Page 55] RFC 7877 SSPF August 2016

 [RFC5246]  Dierks, T. and E. Rescorla, "The Transport Layer Security
            (TLS) Protocol Version 1.2", RFC 5246,
            DOI 10.17487/RFC5246, August 2008,
            <http://www.rfc-editor.org/info/rfc5246>.
 [RFC5486]  Malas, D., Ed. and D. Meyer, Ed., "Session Peering for
            Multimedia Interconnect (SPEERMINT) Terminology",
            RFC 5486, DOI 10.17487/RFC5486, March 2009,
            <http://www.rfc-editor.org/info/rfc5486>.
 [RFC5646]  Phillips, A., Ed. and M. Davis, Ed., "Tags for Identifying
            Languages", BCP 47, RFC 5646, DOI 10.17487/RFC5646,
            September 2009, <http://www.rfc-editor.org/info/rfc5646>.
 [RFC6116]  Bradner, S., Conroy, L., and K. Fujiwara, "The E.164 to
            Uniform Resource Identifiers (URI) Dynamic Delegation
            Discovery System (DDDS) Application (ENUM)", RFC 6116,
            DOI 10.17487/RFC6116, March 2011,
            <http://www.rfc-editor.org/info/rfc6116>.
 [RFC6461]  Channabasappa, S., Ed., "Data for Reachability of Inter-
            /Intra-NetworK SIP (DRINKS) Use Cases and Protocol
            Requirements", RFC 6461, DOI 10.17487/RFC6461, January
            2012, <http://www.rfc-editor.org/info/rfc6461>.
 [RFC7230]  Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
            Protocol (HTTP/1.1): Message Syntax and Routing",
            RFC 7230, DOI 10.17487/RFC7230, June 2014,
            <http://www.rfc-editor.org/info/rfc7230>.
 [SOAPREF]  Gudgin, M., Hadley, M., Moreau, J., and H. Nielsen, "SOAP
            Version 1.2 Part 1: Messaging Framework", W3C REC REC-
            SOAP12-part1-20030624, June 2003,
            <http://www.w3.org/TR/soap12-part1/>.
 [Unicode6.1]
            The Unicode Consortium, "The Unicode Standard, Version
            6.1.0", (Mountain View, CA: The Unicode Consortium,
            2012. ISBN 978-1-936213-02-3),
            <http://unicode.org/versions/Unicode6.1.0/>.

Cartwright, et al. Standards Track [Page 56] RFC 7877 SSPF August 2016

Acknowledgements

 This document is a result of various discussions held in the DRINKS
 working group and within the DRINKS protocol design team, with
 contributions from the following individuals, in alphabetical order:
 Syed Ali, Jeremy Barkan, Vikas Bhatia, Sumanth Channabasappa, Lisa
 Dusseault, Deborah A.  Guyton, Otmar Lendl, Manjul Maharishi, Mickael
 Marrache, Alexander Mayrhofer, Samuel Melloul, David Schwartz, and
 Richard Shockey.

Authors' Addresses

 Kenneth Cartwright
 TNS
 1939 Roland Clarke Place
 Reston, VA  20191
 United States
 Email: kcartwright@tnsi.com
 Vikas Bhatia
 TNS
 1939 Roland Clarke Place
 Reston, VA  20191
 United States
 Email: vbhatia@tnsi.com
 Syed Wasim Ali
 NeuStar
 46000 Center Oak Plaza
 Sterling, VA  20166
 United States
 Email: syed.ali@neustar.biz
 David Schwartz
 XConnect
 316 Regents Park Road
 London  N3 2XJ
 United Kingdom
 Email: dschwartz@xconnect.net

Cartwright, et al. Standards Track [Page 57]

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