[OpenSER-Users] parallel forking

[Iñaki Baz Castillo]

El Thursday 15 May 2008 05:39:32 Allan Chao escribió:
> Dear All:
>
> I have found there are some devices can't process two 180 ringing  after
> use OPENSER  to do parallel forking, so,  i have a idea that is used
> OPENSER to delete To tag in the To header before relay it , and it works
> well  with eyebeam. But i can't find any spec to support my idea because it
> is against "early dialog" prograss  and  my question is
>
> how does UE(eyebeam or some client) to create dialog if there is no any To
> tag in 180 ringing but 200 OK has  in the latter ?    i think the UA will
> generate local ring tone but no any dialog after receives 180 ringing with
> no To tag?  is it right ? thanks,

A "180 Ringing" without To tag is completely anti RFC 3261 compliant so you 
shouldn't do it:

 8.2.6.2 Headers and Tags
    ...
   However, if the To
   header field in the request did not contain a tag, the URI in the To
   header field in the response MUST equal the URI in the To header
   field; additionally, the UAS MUST add a tag to the To header field in
   the response (with the exception of the 100 (Trying) response, in
   which a tag MAY be present).  This serves to identify the UAS that is
   responding, possibly resulting in a component of a dialog ID.  The
   same tag MUST be used for all responses to that request, both final
   and provisional (again excepting the 100 (Trying)).


If you have a device not allowing various 180 with different To tag, this is, 
a device not allowing parallel forking, then it's a bug in that device.




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