[asterisk-dev] [Code Review] SIP: proper handling of forked outbound INVITE requests.

[Olle E. Johansson]

29 sep 2010 kl. 16.54 skrev David Vossel:

> 
> 
>> On 2010-09-28 17:48:39, Kevin Fleming wrote:
>>> I've given the code a once-over and it looks sane, but the description made me ask another question: what will happen when Asterisk receives provisional responses to the forked INVITE? These establish an 'early dialog' but otherwise don't need any action... will Asterisk just drop them safely (and not disturb the sip_pvt's contents for the *real* early dialog we plan to keep)?
> 
> I don't see how it is possible to have multiple early dialogs for a single outbound INVITE request. The to-tags for provisional responses can change later, and should not be held on to from what I understand.  Since the final establishment of the to-tag is used to distinguish the forked request, I don't know how this could be done in any other way before the 200 OK.
> 



You send an INVITE that forks to multiple servers

- server 1 responds with 183 + sdp after two seconds
- server 2 responds with 180 ringing after four seconds
- server 3 responds with 183 + sdp after six seconds
- server 4 responds with 200 OK.

Now, in worst case, you might get 200 OK from two servers.

This is a test we're setting up at every SIPit :-)

/O