The current info-events text says (section 5.6): "In addition, the INFO method does not define mechanisms for ensuring in-order delivery. While the UAC will increment the CSeq header upon the transmission of new INFO messages, the UAS cannot use the CSeq to determine the sequence of INFO information. This is due to the fact that there could be gaps in the INFO message CSeq count caused by a user agent sending re-INVITES or other SIP messages."
This is not entirely accurate: SIP guarantees that INFO messages are never delivered out-of-sequence. Only in case of *overlapping INFO requests* (i.e. sending a next one before having received a final response for the previous one) it cannot be guaranteed that all are received.
The partial event mechanism (RFC5263) includes a 'version' attribute to detect such gaps. In case of INFO events, I think it is better to simply say: the UAC MUST NOT send an INFO request with a given event type when a previous INFO request containing that event type has not yet received a final response.
Regards, Jeroen _______________________________________________ Sip mailing list https://www.ietf.org/mailman/listinfo/sip This list is for NEW development of the core SIP Protocol Use [EMAIL PROTECTED] for questions on current sip Use [EMAIL PROTECTED] for new developments on the application of sip
