[SIPForum-discussion] Session-expires inclusion in UPDATE

[José Antonio Jíménez Rodríguez]

Hi all

I have a question for you

VoLTE-VoLTE call, preconditions are used (so, A-party will send an UPDATE when preconditions are fullfilled on A-party side)

Should a VoLTE UE add Session-expires on that UPDATE?

3GPP documents are not clear on that:
*24.229 does not detail the contents of the UPDATE that A-party should send when preconditions are fullfilled
*24.930 (Signalling flows for the session setup in the IP Multimedia core network Subsystem (IMS) based on Session Initiation Protocol (SIP) ), does not include Session-Expires on any message but some cases (INVITE when no preconditions are used)

I can see different VoLTE UE behaviour, and when UE does not add it on this precondition-UPDATE, in some implementations, the network adds it...

Best regards and thanks.