Content for TS 29.338 Word version: 18.2.0

3.1 Definitions 3.2 Abbreviations 4.1 Introduction 4.2 Use of Diameter Base protocol 4.3 Securing Diameter messages 4.4 Accounting functionality 4.5 Use of sessions 4.6 Transport protocol 4.7 Advertising application support 4.8 Diameter Application Identifier 4.9 Use of the Supported-Features AVP
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1 Scope p. 7

The present document defines the Diameter-based interfaces specific to SMS when they are used in conjunction with the "SMS in MME" architecture specified in TS 23.272 or for SGSN supporting EPS interfaces, or the" SMS in 5GS" architecture specified in TS 23.501. It comprises:

the Diameter application for the S6c interface between the HSS/UDM and the central SMS functions (SMS-GMSC, SMS Router);
the Diameter application
- for the SGd interface between the MME/SMSF, the SMS-IWMSC, the SMS-GMSC and the SMS Router.
- for the Gdd interface between the SGSN, the SMS-IWMSC, the SMS-GMSC and the SMS Router.

For the purpose of supporting SMS in 5GS, the UDM may implement the requirements specified in the present specification for HSS, with the following modification:

"HSS" is to be replaced with "UDM".

2 References p. 7

The following documents contain provisions which, through reference in this text, constitute provisions of the present document.

References are either specific (identified by date of publication, edition number, version number, etc.) or non-specific.
For a specific reference, subsequent revisions do not apply.
For a non-specific reference, the latest version applies. In the case of a reference to a 3GPP document (including a GSM document), a non-specific reference implicitly refers to the latest version of that document in the same Release as the present document.

[1]

TR 21.905: "Vocabulary for 3GPP Specifications".

[2]

TS 23.272: "Circuit Switched (CS) fallback in Evolved Packet System (EPS); Stage 2".

[3]

TS 23.040: "Technical realization of the Short Message Service (SMS)".

[4]

TS 29.272: "Evolved Packet System (EPS); Mobility Management Entity (MME) and Serving GPRS Support Node (SGSN) related interfaces based on Diameter protocol".

[5]

TS 29.229: "Cx and Dx interfaces based on the Diameter protocol; Protocol details".

[6]

RFC 2234: "Augmented BNF for Syntax Specifications: ABNF".

[7] Void.

[8]

RFC 5516: "Diameter Command Code Registration for the Third Generation Partnership Project (3GPP) Evolved Packet System (EPS)".

[9]

TS 29.002: "Mobile Application Part (MAP) specification".

[10]

TS 29.173: "Location Services (LCS); Diameter-based SLh interface for Control Plane LCS".

[11]

TS 33.210: "3G security; Network Domain Security (NDS); IP network layer security ".

[12]

RFC 4960: "Stream Control Transport Protocol".

[13]

ITU-T Recommendation E.164: "The international public telecommunication numbering plan".

[14]

TS 29.329: "Sh Interface based on the Diameter protocol; Protocol details".

[15]

TS 29.336: "Home Subscriber Server (HSS) diameter interfaces for interworking with packet data networks and applications".

[16]

TS 23.003: "Numbering, addressing and identification".

[17]

TS 23.204: "Support of Short Message Service (SMS) over generic 3GPP Internet Protocol (IP) access; Stage 2".

[18]

TS 23.682: "Architecture enhancements to facilitate communications with packet data networks and applications".

[19]

RFC 7944: "Diameter Routing Message Priority".

[20]

RFC 6733: "Diameter Base Protocol".

[21]

TS 23.501: "System Architecture for the 5G System".

3 Definitions, symbols and abbreviations p. 8

3.1 Definitions p. 8

For the purposes of the present document, the terms and definitions given in TR 21.905 and the following apply. A term defined in the present document takes precedence over the definition of the same term, if any, in TR 21.905.

3.2 Abbreviations p. 8

For the purposes of the present document, the abbreviations given in TR 21.905 and the following apply. An abbreviation defined in the present document takes precedence over the definition of the same abbreviation, if any, in TR 21.905.

ABNF

Augmented Backus-Naur Form

DRMP

Diameter Routing Message Priority

DSCP

Differentiated Services Code Point

IANA

Internet Assigned Numbers Authority

IP-SM-GW

IP Short Message Gateway

MWD

Message Waiting Data

Relay layer Protocol

RP-MTI

RP Message Type Indicator

RP-SMEA

RP SME-Address

RP-UI

RP User Information

SM RL

Short Message Relay Layer

SMS-GMSC

Gateway MSC for SMS

SMS-IWMSC

Interworking MSC for SMS

SMSMI

SMS without MSISDN in IMS

4 General p. 9

4.1 Introduction p. 9

The SMS in MME architecture is described in TS 23.272 and the SMS in 5GS architecture is described in TS 23.501, have specified the reference points S6c and SGd.

The clause 4 addresses Diameter aspects which are common to S6c, SGd and Gdd.

4.2 Use of Diameter Base protocol p. 9

The Diameter base protocol as specified in RFC 6733 shall apply except as modified by the defined support of the methods and the defined support of the commands and AVPs, result and error codes as specified in this specification. Unless otherwise specified, the procedures (including error handling and unrecognised information handling) shall be used unmodified.

4.3 Securing Diameter messages p. 9

For secure transport of Diameter messages, see TS 33.210.

4.4 Accounting functionality p. 9

Accounting functionality (Accounting Session State Machine, related command codes and AVPs) shall not be used on the S6c, SGd and Gdd interfaces.

4.5 Use of sessions p. 9

Diameter sessions shall be implicitly terminated over the S6c, SGd and Gdd interfaces. An implicitly terminated session is one for which the server does not maintain state information. The client shall not send any re-authorization or session termination requests to the server.

The Diameter base protocol specified in RFC 6733 includes the Auth-Session-State AVP as the mechanism for the implementation of implicitly terminated sessions.

The client (server) shall include in its requests (responses) the Auth-Session-State AVP set to the value NO_STATE_MAINTAINED (1), as described in RFC 6733. As a consequence, the server shall not maintain any state information about this session and the client shall not send any session termination request. Neither the Authorization-Lifetime AVP nor the Session-Timeout AVP shall be present in requests or responses.

4.6 Transport protocol p. 9

Diameter messages over the S6c, SGd and Gdd interfaces shall make use of SCTP as specified in RFC 4960 as transport protocol.

4.7 Advertising application support p. 9

The MME, HSS, SMS-IWMSC, SMS-GMSC and SMS Router shall advertise support of the Diameter S6c Application over the S6c interface and of the Diameter SGd Application over the SGd interface by including the value of the application identifier in the Auth-Application-Id AVP within the Vendor-Specific-Application-Id grouped AVP of the Capabilities-Exchange-Request and Capabilities-Exchange-Answer commands. The MME, SMS-GMSC and SMS Router shall additionally advertise support of the Diameter S6c Application over the SGd interface if they support the Alert Service Centre procedure between the MME, SMS-GMSC and SMS Router.

The SGSN, SMS-IWMSC, SMS-GMSC and SMS Router shall advertise support of the Diameter SGd Application over the Gdd interface by including the value of the application identifier in the Auth-Application-Id AVP within the Vendor-Specific-Application-Id grouped AVP of the Capabilities-Exchange-Request and Capabilities-Exchange-Answer commands. The SGSN, SMS-GMSC and SMS Router shall additionally advertise support of the Diameter S6c Application over the Gdd interface if they support the Alert Service Centre procedure between the SGSN, SMS-GMSC and SMS Router.

The MTC-IWF and SMS-IWMSC shall advertise support of the Diameter SGd Application over the T4 interface if they support the MO-Forward-Short-Message procedure between the SMS-IWMSC and the MTC-IWF.

The vendor identifier value of 3GPP (10415) shall be included in the Supported-Vendor-Id AVP of the Capabilities-Exchange-Request and Capabilities-Exchange-Answer commands, and in the Vendor-Id AVP within the Vendor-Specific-Application-Id grouped AVP of the Capabilities-Exchange-Request and Capabilities-Exchange-Answer commands.

The Vendor-Id AVP included in Capabilities-Exchange-Request and Capabilities-Exchange-Answer commands that is not included in the Vendor-Specific-Application-Id AVPs as described above shall indicate the manufacturer of the Diameter node as per RFC 6733.

4.8 Diameter Application Identifier p. 10

The S6c and the SGd/Gdd interface protocols shall be defined, each, as an IETF vendor specific Diameter application, where the vendor is 3GPP. The vendor identifier assigned by IANA to 3GPP (http://www.iana.org/assignments/enterprise-numbers) is 10415.

The Diameter application identifier assigned to the S6c Diameter application is 16777312 (allocated by IANA).

The Diameter application identifier assigned to the SGd Diameter application, which is also applicable to the Gdd and T4 interfaces is 16777313 (allocated by IANA).

4.9 Use of the Supported-Features AVP p. 10

When new functionality is introduced on the S6c or SGd Diameter applications, it should be defined as optional. If backwards incompatible changes can not be avoided, the new functionality shall be introduced as a new feature and support advertised with the Supported-Features AVP. The usage of the Supported-Features AVP on the S6c or SGd applications is consistent with the procedures for the dynamic discovery of supported features as defined in clause 7.2 of TS 29.229.

When extending the application by adding new AVPs for a feature, the new AVPs shall have the M bit cleared and the AVP shall not be defined mandatory in the command ABNF.

As defined in TS 29.229, the Supported-Features AVP is of type grouped and contains the Vendor-Id, Feature-List-ID and Feature-List AVPs. On the all reference points as specified in this specification, the Supported-Features AVP is used to identify features that have been defined by 3GPP and hence, for features defined in this document, the Vendor-Id AVP shall contain the vendor ID of 3GPP (10415). If there are multiple feature lists defined for the reference point, the Feature-List-ID AVP shall differentiate those lists from one another.

The Table 5.3.3.13/1 defines the features applicable to the S6c interface for the feature list with a Feature-List-ID of 1.