I've got a SIP servlet which places a third party call by inviting two 
other SIP agents into a B2BUA dialog.  Say that the two other SIP agents 
are sip:[EMAIL PROTECTED] and sip:[EMAIL PROTECTED]

The B2BUA stuff that I've seen involves sending an INVITE with no SDP to 
usr1, taking the returned SDP and sending it to usr2, etc.  I have to pull 
the SDP from one user and then pass it along to the other.

Suppose sip:[EMAIL PROTECTED] can be an address-of-record which has 
sip:[EMAIL PROTECTED], sip:[EMAIL PROTECTED], and 
sip:[EMAIL PROTECTED] REGISTERed to it.  Similiarly with usr2.    Then 
the approach described above gets a non-deterministic SDP from usr1 and 
then passes it along to usr2.  The SDP used is the first device REGISTERed 
to usr1 that answers.

What if I require particular media capabilites (e.g. voice) and the 
devices aren't guarenteed to provide voice capability.   I'm looking for a 
compatible SDP with particular (e.g. voice) capability which may or may 
not exist among [EMAIL PROTECTED] and [EMAIL PROTECTED]

I've been able to think of querying the registrar for all of the devices 
available for [EMAIL PROTECTED], sending each of them an OPTIONS message, 
examining the SDPs, and then only using the voice-capable devices for a 
parallel invite.  Ditto for [EMAIL PROTECTED]  Then I've reduced the problem 
to 

Is there an easier, more straightforward, more cannonical way to say that 
I'd like to find (if any exists) media-specific SDP addresses associated 
with two addresses-of-record?

Thanks,
Rhys
__________________________________
Rhys Ulerich
Telecommunications Solutions Software Development
Email: [EMAIL PROTECTED]  Office: 512-828-1428
IBM Software Group - Austin, TX

_______________________________________________
Sip-implementors mailing list
[EMAIL PROTECTED]
http://lists.cs.columbia.edu/mailman/listinfo/sip-implementors

Reply via email to