[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
RE: [Sip] Out of sequence datagrams
This is what suspected. Yes the NOTIFY is a result of the implicit
SUBSCRIPTION caused by the REFER. So from an implementation perspective,
what is/should be the CSEQ relationship between NOTIFY CSEQ and the INVITE
dialog? (If there is none, the UAS would need to differentiate NOTIFY CSEQ's
from the INVITE/BYE even though the call identifers are the same.)
-----Original Message-----
From: Brett Tate [mailto:brett@broadsoft.com]
Sent: Tuesday, May 20, 2003 12:12 PM
To: sip@ietf.org
Subject: RE: [Sip] Out of sequence datagrams
> Please refer to the snippet from
> "12.2.2 UAS Behavior" of RFC3261
>
> ....
> If the remote sequence number is empty,
> it MUST be set to the value of the sequence
> number in the CSeq header field value in
> the request.
> If the remote sequence number was not empty,
> but the sequence number of the request is lower
> than the remote sequence number, the request
> is out of order
> ....
>
> Because the ordering of UDP datagrams isn't
> guarenteed, it is possible for the above to occur.
> For example NOTIFY with CSEQ 2 is received after
> the BYE with CSeq 3. Since, from the application
> perpective, the dialog has ended, there appears no
> way the NOTIFY can be processed by the UAS.
If order is important, requests should
be queued until the prior request has been
acknowledged. However concerning your BYE
and NOTIFY example, the BYE only terminates
the call associated with the dialog. The
BYE does not necessarily terminate subscriptions
associated with the dialog. Thus if the NOTIFY
relates to the implicit subscription caused
by a REFER, the notifies can continue to be
sent after the BYE has released the call
associated with the dialog.
_______________________________________________
Sip mailing list https://www1.ietf.org/mailman/listinfo/sip
This list is for NEW development of the core SIP Protocol
Use sip-implementors@cs.columbia.edu for questions on current sip
Use sipping@ietf.org for new developments on the application of sip
_______________________________________________
Sip mailing list https://www1.ietf.org/mailman/listinfo/sip
This list is for NEW development of the core SIP Protocol
Use sip-implementors@cs.columbia.edu for questions on current sip
Use sipping@ietf.org for new developments on the application of sip