5 Functional entities

24.2823GPPMission Critical Data (MCData) signalling controlProtocol specificationRelease 18TS

5.1 Introduction

This clause associates the functional entities with the MCData roles described in the stage 2 architecture document (see 3GPP TS 23.282 [2]).

5.2 MCData client

To be compliant with the procedures in the present document, an MCData client shall:

– act as the user agent for all MCData application transactions (e.g. initiation of a group standalone SDS message); and

– support handling of the MCData client ID as described in clause 4.8.

To be compliant with the on-network procedures in the present document, an MCData client shall:

– support the MCData client on-network procedures defined in 3GPP TS 23.282 [2];

– support the GCS UE procedures defined in 3GPP TS 23.468 [56] for unicast delivery, MBMS delivery and service continuity;

– support the on-network MCData message formats specified in clause 15 for the short data service (SDS) and the file distribution service (FD);

– act as a SIP UA as defined in 3GPP TS 24.229 [5];

– generate SDP offer and SDP answer in accordance with 3GPP TS 24.229 [5] and:

a) clause 9.2.3 and clause 9.2.4 for short data service; and

b) clause 10.2.5 for file distribution.

– for registration and service authorisation, implement the procedures specified in clause 7.2;

– for affiliation, implement the procedures specified in clause 9.2;

– for short data service (SDS) functionality implement the MCData client procedures specified in:

a) clause 9.2; and

b) clause 6 of 3GPP TS 24.582 [15];

– for file distribution (FD) functionality implement the MCData client procedures specified in:

a) clause 10.2; and

b) clause 7 of 3GPP TS 24.582 [15];

– for transmission and reception control functionality implement the MCData client procedures specified in clause 11;

– for disposition notification functionality implement the MCData client procedures specified in clause 12.2;

– for communication release functionality implement the MCData client procedures specified in clause 13.2; and

– for functional alias management, implement the procedures specified in clause 22.2.1.

To be compliant with the off-network procedures in the present document, an MCData client shall:

– support the off-network procedures defined in 3GPP TS 23.282 [2];

– support the off-network MONP MCData message formats specified in clause 15;

– implement the procedures for ProSe direct discovery for public safety use as specified in 3GPP TS 24.334 [25];

– implement the procedures for one-to-one ProSe direct communication for Public Safety use as specified in 3GPP TS 24.334 [25]; and

– for short data service (SDS) functionality implement the MCData client procedures specified in clause 9.3.

To be compliant with the on-network and off-network procedures in the present document requiring end-to-end security key distribution, an MCData client shall support the procedures specified in 3GPP TS 33.180 [26].

To be compliant with the procedures for confidentiality protection of XML elements in the present document, the MCData client shall implement the procedures specified in clause 6.5.2.

To be compliant with the procedures for integrity protection of XML MIME bodies in the present document, the MCData client shall implement the procedures specified in clause 6.5.3.

5.3 MCData server

5.3.0 General

An MCData server can perform the controlling role for short data service and file distribution as defined in 3GPP TS 23.282 [2].

An MCData server can perform the participating role for short data service and file distribution as defined in 3GPP TS 23.282 [2].

An MCData server performing the participating role can serve an originating MCData user.

An MCData server performing the participating role can serve a terminating MCData user.

The same MCData server can perform the participating role and controlling role for the same group short data service transaction or group file distribution transaction.

When referring to the procedures in the present document for the MCData server acting in a participating role for the served user, the term, "participating MCData function" is used.

When referring to the procedures in the present document for the MCData server acting in a controlling role for the served user, the term "controlling MCData function" is used.

To be compliant with the procedures in the present document, an MCData server shall:

– support the MCData server procedures defined in 3GPP TS 23.282 [2];

– support the GCS AS procedures defined in 3GPP TS 23.468 [56] for unicast delivery, MBMS delivery and service continuity;

– implement the role of an AS performing 3rd party call control acting as a routing B2BUA as defined in 3GPP TS 24.229 [5];

– generate SDP offer and SDP answer in accordance with 3GPP TS 24.229 [5] and:

a) clause 9.2.3 and clause 9.2.4 for short data service; and

b) clause 10.2.5 for file distribution.

– for registration and service authorisation, implement the procedures specified in clause 7.3;

– for affiliation, implement the procedures specified in clause 9.2.2;

– for short data service (SDS) functionality implement the MCData server procedures specified in:

a) clause 9.2; and

b) clause 6 of 3GPP TS 24.582 [15];

– for file distribution (FD) functionality implement the MCData server procedures specified in:

a) clause 10.2; and

b) clause 7 of 3GPP TS 24.582 [15];

– for transmission and reception control functionality implement the MCData server procedures specified in clause 11;

– for disposition notification functionality implement the MCData server procedures specified in clause 12.2;

– for communication release functionality implement the MCData server procedures specified in clause 13.2; and

– for functional alias management, implement the procedures specified in clause 22.2.2.

To be compliant with the procedures in the present document requiring the distribution of keying material between MCData clients as specified in 3GPP TS 33.180 [26], an MCData server shall ensure that the keying material is copied from the incoming MCData messages into the outgoing MCData messages.

To be compliant with the procedures for confidentiality protection of XML elements in the present document, the MCData server shall implement the procedures specified in clause 6.5.2.

To be compliant with the procedures for integrity protection of XML MIME bodies in the present document, the MCData server shall implement the procedures specified in clause 6.5.3.

5.3.1 SIP failure case

When initiating a SIP failure response to any received SIP request, depending on operator policy, the MCData server may insert a SIP Response-Source header field in accordance with the procedures in clause 5.7.1.0 of 3GPP TS 24.229 [5], where the "role" header field parameter is set to "pf-mcdata-server" or "cf-mcdata-server" depending on the current role endorsed by the MCData server.

5.3.1A SIP provisional response

When sending SIP provisional responses, with the exception of the SIP 100 (Trying) response to the SIP INVITE request, the MCData server acting in the controlling MCData function role:

1) shall generate the SIP provisional response;

2) shall include a P-Asserted-Identity header field with the public service identity of the controlling MCData function;

3) shall include an MCData session identity in the Contact header field; and

4) shall include the following in the Contact header field:

a) the g.3gpp.mcdata media feature tag;

b) the g.3gpp.icsi-ref media feature tag containing the value of "urn:urn-7:3gpp-service.ims.icsi.mcdata"; and

c) the isfocus media feature tag.

5.3.2 Management of MBMS bearers

When providing services over MBMS, an MCData server acting in the participating MCData function role shall:

– allocate TMGIs and activate MBMS bearers in MBMS service areas to be used for MCData media plane transmissions via multicast, per 3GPP TS 23.468 [56] and 3GPP TS 29.468 [57];

– deactivate MBMS bearers and deallocate TMGIs when no longer necessary, per 3GPP TS 23.468 [56] and 3GPP TS 29.468 [57];

– handle MBMS bearers related notifications per 3GPP TS 23.468 [56] and 3GPP TS 29.468 [57]; and

– adjust the priority / pre-emption characteristics of MBMS bearers, as appropriate, in response to relevant events, using procedures specified in per 3GPP TS 23.468 [56] and 3GPP TS 29.468 [57].

5.4 MCData gateway server

5.4.1 General

To allow interconnection between MCData system in different trust domains, MC Gateway Servers can be optionally added on the path between controlling and participating MCData functions and between controlling and non-controlling MCData functions.

An MCData gateway server acts as a SIP and HTTP proxy for signalling with an interconnected MCData system in a different trust domain.

An MCData gateway server acts as an application and security gateway with an interconnected MCData system in a different trust domain.

An MCData gateway server provides topology hiding to the interconnected MCData system in a different trust domain.

An MCData gateway server enforces local policies and local security.

An MCData gateway server can be an exit point from its MCData system to an interconnected MCData system in a different trust domain, an entry point to its MCData system from an interconnected MCData system in a different trust domain, or both.

An MCData gateway server is transparent to controlling and participating MCData functions and to controlling and non-controlling MCData functions. When required for interconnection, MC gateway servers URIs are known and used by MCData servers in place of the PSIs of the interconnected MCData server. The MCData server does not need to know if it finally addresses directly a controlling MCData function or an intermediate MCData gateway server.

To be compliant with the procedures in the present document, an MCData gateway server shall:

– support the MC gateway server procedures defined in 3GPP TS 23.280 [3] and 3GPP TS 23.282 [2]; and

– support the MC gateway server procedures defined in 3GPP TS 33.180 [26];

– implement the procedures specified in clause 6.8.

To be compliant with the procedures for confidentiality protection in the present document, the MCData gateway server shall implement the procedures specified in clause 6.5.2, acting on behalf of the MCData server when sending or receiving confidentiality protected content to or from an MCData server in another trust domain.

To be compliant with the procedures for integrity protection of XML MIME bodies in the present document, the MCData gateway server shall implement the procedures specified in clause 6.5.3, acting on behalf of the MCData server when sending or receiving integrity protected content to or from an MCData server in another trust domain.