[SIPForum-discussion] [SIP Forum Discussion] INVITE request followed by CANCEL

Tomasz Zieleniewski tzieleniewski at gmail.com
Wed Apr 15 11:07:58 UTC 2009


2009/4/14 Ashutosh Panda <ashubdk at gmail.com>:
> Hello Everybody,
> I have doubts in following two issues. Hope I can find my answer through
> this forum. Thanks in advance.
> Question 1.
> Forking is supported.
> Originator calls recipient which is registered at many places.
> Server attempts the calls at all the registered places of recipient but it
> receives No Answer/Busy from all places.
> Now, will the server send 486 Busy or 603 Decline response to the originator
> of the call?
When SIP proxy fork requests because some AOR is registered under
different location
only provisional responses other than 100 (Trying) and any 2xx
response are immediately forwarded upstream
to the caller. All other requests are added to response context until
all transactions finish.
Finally stateful proxy chooses the final response among those received
and stored in the response context.
If there is no 6xx class responses, the proxy chooses from the lowest
response class stored in the response context.
That is way here if all request where answered by 486 Busy UAC will
also receive 486 Busy.

> Question 2:
> Originator calls recipient.
> Recipient does not answer the call (though recipient sends 180 Ringing)
> When timeout occurs, will the server send any error response (or CANCEL
> request) to the callee and called parties or the callee will initiate call
> termination process.
In this case timer B, which controls transaction timeouts, occurs.
Because there are no final responses in the response context, the
proxy (server) will
send a 408 (Request Timeout) response to the upstream to the caller.

Kind regards
- Tomasz Zieleniewski

> Regards
> Ashutosh Panda
> _______________________________________________
> This is the SIP Forum discussion mailing list
> TO UNSUBSCRIBE, or edit your delivery options, please visit
> http://sipforum.org/mailman/listinfo/discussion
> Post to the list at discussion at sipforum.org

More information about the discussion mailing list