24.2813GPPMission Critical Video (MCVideo) signalling controlProtocol specificationRelease 18TS
Editor’s note: [CT1#133-e, C1-217178, CR0146 rev 1]: The info package type "application/vnd.3gpp.mcvideo-transmission-request+xml" as defined in this clause is to be registered in the IANA registry for Application Media Types based upon the following template. The registration is to be started at the completion of 3GPP release 17.
This clause contains the information required for the IANA registration of info package g.3gpp.mcvideo-transmission-request in accordance with IETF RFC 6086 .
I.1.2 g.3gpp.mcvideo-transmission-request info package
I.1.2.1 Overall description
When a temporary group call includes constituent MCVideo groups in partner systems where an MCVideo call is ongoing and if there is a participant with permission to transmit, the non-controlling MCVideo function of an MCVideo group needs to transfer information of the currently transmitting user(s) to the controlling MCVideo function hosting the temporary group. The information is transferred in the form of a transmission request.The controlling MCVideo function will then determine if the participant will be permitted to continue to transmit or if the permission to transmit is revoked.
This package is used to transport a transmission request from the non-controlling MCVideo function of an MCVideo group to the controlling MCVideo function hosting the temporary group.
I.1.2.3 Appropriateness of INFO Package Usage
A number of solutions were discussed for the transportation of the transmission request to the controlling MCVideo function hosting the temporary MCVideo group. The solutions were:
1) Use of the session related methods (e.g. SIP 200 (OK) response to the SIP INVITE request).
2) Use of the SIP MESSAGE method.
3) 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) To include such a large amount of data in a SIP 200 (OK) response to an SIP INVITE request could cause problems with the size of the SIP 200 (OK) response resulting in packet fragmentation.
2) The use of the SIP MESSAGE request would result in that the recommended value of size of the information transferred by the SIP MESSAGE request would be exceeded.
3) 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.
I.1.2.4 Info package name
I.1.2.5 Info package parameters
I.1.2.7 INFO message body parts
The MIME type of the message body carrying participant identities is application/vnd.3gpp.mvideo-transmission-request+xml. The application/vnd.3gpp.mcvideo-transmission-request+xml MIME type is defined in 3GPP TS 24.281.
When associated with the g.3gpp.mcvideo-transmission-request info package, the Content-Disposition value of the message body carrying the floor request is "info-package".
I.1.2.8 Info package usage restrictions
I.1.2.9 Rate of INFO Requests
Single INFO request generated after session set up.
I.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.
I.1.2.11 Implementation details and examples
UAC generation of INFO requests: See 3GPP TS 24.281: "Mission Critical Video (MCVideo) signalling control; Protocol specification".
UAS processing of INFO requests: See 3GPP TS 24.281: "Mission Critical Video (MCVideo) signalling control; Protocol specification".
EXAMPLE: A controlling MCVideo function hosting a temporary MCVideo group inviting a constituent MCVideo group hosted by a non-controlling MCVideo function of an MCVideo group in a partner system where an MCVideo call is ongoing with one or two of the participants granted to transmit. Then the non-controlling MCVideo function of the constituent MCVideo group sends a SIP INFO request carrying a transmission request in an application/vnd.3gpp.mcvideo-transmission-request+xml MIME body using the g.3gpp.mcvideo-transmission-request info package.