My
question is : Is it possible to send Update without any offer when a re-invite
or Update having an offer is pending?
According to Session-Timer --
draft-ietf-sip-session-timer-09.txt, Update is recommended to be used as the
refresher request instead of a re-invite. It is recommended that Update
used for refresh should not have SDP.
Update
draft suggests that
"if the UPDATE is being sent after
the completion of the initial INVITE transaction,
it cannot be sent if the
caller has generated or received offers in a re-INVITE or
UPDATE which have not been
answered. "
This
is justified when Update is used only for offer-answer purpose, but can be
overridden while being used for session timer.
Thanks,
Sani
