[OpenSIPS-Users] [OpenSIPS-Devel] Planning next release - Roadmap

[Iñaki Baz Castillo]

El Tuesday 26 August 2008 16:30:55 Ovidiu Sas escribió:
> This is a little bit tricky, because you need to keep tracking of the
> cseq for the received and sent message (each OPTION will increase the
> sent cseq number).  Each in dialog request that will come from the far
> end UAC will need to have the cseq altered to be in synch with the
> previous sent OPTION.
> It can be done, but it is more work.  Sending OPTIONS from the dialog
> module itself is quite easy.  I implemented and tested that, but then
> I got lazy in implementing the cseq mangling stuff.

If a proxy changes the CSeq in a request it must also change it in the 
responses to the client.

Also note the problem handling PRACK since a PRACK message is an in-dialog 
request containing CSeq and Rseq, and the reply must contain Cseq and RAck. 
Example:

UAC  -------->   UAS

  INVITE --->
  Cseq: 10

     <-- 180
          CSeq: 10
          Require: 10res
          Rseq: 555

  PRACK --->
  Cseq: 11
  RAck: 555 10


So IMHO it's not so easy to handle and modify it in a proxy. Also this seems 
to me more a B2BUA task.


-- 
Iñaki Baz Castillo
ibc at in.ilimit.es