On 01/01/2010 11:32 AM, Antonio Goméz Soto wrote:
I am sorry, maybe I do not understand enough about SIP and proxies. Wouldn't it be possible to fake re-invites? Tell each phone that it gets a reinvite coming from the other phone, and basically redirecting the sound stream to an rtpproxy for example? or a codec translator?
I'd like to switch from g711 to g729 when the link gets overloaded for example. Or record the phonecall.
I am trying to learn more about SIP. Aren't reinvites within a dialog common?
Maybe I could make changes to openser to enable this?
Yes, reinvites are common, and you have correctly ascertained their purpose.
What I think you are not understanding is that a reinvite, like any other request, must be originated from an endpoint (a user agent). A proxy is not a user agent; it cannot generate replies. The only thing proxies do, as a matter of definition, is forward requests they receive, and forward replies to them in the opposite direction (when applicable).
Again, I draw your attention to the HTTP server vs. Squid analogy we made earlier. The question you are asking sounds equivalent to, "Can Squid send a GET request?" The answer is no, Squid cannot send any requests; it can only act on requests it receives and direct them somewhere.