H.1 Info package for indication of communication release

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

H.1.1 Scope

This clause contains the information required for the IANA registration of info package g.3gpp.mcdata-com-release in accordance with IETF RFC 6086.

H.1.2 g.3gpp.mcdata-com-release info package

H.1.2.1 Overall description

When one of the communication release conditions are met e.g. lack of bearer capacity, limit for the maximum amount of data or time that a participant transmits from a single request to transmit exceeded, the MCData server may decide to release communication. Based on local policy and configuration, MCData server can release the communication without prior notification to MCData user; or it may send a notification to MCData user and allow the user to request for extension if the MCData user wants to. With this notification, MCData server may also request for more information related to ongoing communication like amount of data remainnig to be transmitted. If MCData user requests for extension of the MCData communication, MCData server can accept or reject based on local policy.

H.1.2.2 Applicability

This package is used to:

– send MCData server’s intent to release the communication to the MCData client

– send more data from MCData client to MCData server when requested

– request extension of the MCData communication to MCData server.

– send response for extension request from MCData server to MCData client.

H.1.2.3 Appropriateness of INFO Package Usage

A number of solutions were discussed for sending MCData server’s intent to release the communication along with request for more data to MCData user. The solutions were:

1) Use of the session related methods (e.g. SIP RE-INVITE 200 (OK) response.

2) Use of the SIP INFO method as described in IETF RFC 6086, by defining a new info package.

The result of the evaluation of the above solutions were:

1) An SIP INVITE request will have three-way handshake, which may not be optimal to transfer the required data.

2) The use of SIP INFO request was found as the most appropriate solution since the SIP INFO request could be sent in the existing SIP session and can carry QUERY response in 200 OK.

H.1.2.4 Info package name

g.3gpp.mcdata-com-release

H.1.2.5 Info package parameters

None defined

H.1.2.6 SIP options tags

None defined

H.1.2.7 INFO message body parts

The MIME type of the message body carrying application/vnd.3gpp.mcdata-signalling and application/vnd.3gpp.mcdata-payload. Both application/vnd.3gpp.mcdata-signalling and application/vnd.3gpp.mcdata-payload MIME type is defined in this specification.

H.1.2.8 Info package usage restrictions

None defined.

H.1.2.9 Rate of INFO Requests

Single INFO request generated after MCData server decides to release communication with prior notification to MCData client and not requesting for more data.

Two INFO requests generated after MCData server decides to release communication with prior notification to MCData client and requesting more data.

Two INFO requests generated after MCData client requests for extension of communication.

H.1.2.10 Info package security considerations

The security is based on the generic security mechanism provided for the underlying SIP signalling. No additional security mechanism is defined.

H.1.2.11 Implementation details and examples

UAC generation of INFO requests: See 3GPP TS 24.282: "Mission Critical Data (MCData) signalling control; Protocol specification".

UAS processing of INFO requests: See 3GPP TS 24.282: "Mission Critical Data (MCData) signalling control; Protocol specification".

Annex I (normative):
MCData session control specific concepts for the support of mission critical services over 5GS