I am a bit unclear on the use of re-Invite to "modify" a specific sip header value. (example is the case of OMA POC where session-expires header is used to inform the server about the request session expires interval). UPDATE can be used but it is discouraged to be used after session establishment in favor of re-Invite per UPDATE specification.
Using re-Invite for session refresh brings out the issue of the sdp that was previously negotiated: A) If no sdp is provided in the re-INVITE (since the purpose of this type of re-INVITE is not negotiating sdp parameters but modify sip header only), RFC3261 indicates that an offer will come in the response to the re-INVITE. This is not desired. Hence this option is not taken. B) Is it ok to re-offer identical sdp offer as the first INVITE? Is there a GUARANTEED way to ensure that the receiving end will NOT process is this identical sdp and send a different answer? The specifications are not clear on the no-op case. Can someone comment on the use of re-INVITE to modify a sip header and not have to deal with sdp offer/answer re-negptiation? Thanks. Ansari SonyEricsson _______________________________________________ Sip-implementors mailing list [email protected] http://lists.cs.columbia.edu/mailman/listinfo/sip-implementors
