[SIPForum-discussion] Media renegotiation after Call Forward no-answer (bis)

Shaily Singh shailysingh at in.ibm.com
Tue Jun 30 06:16:21 UTC 2009


There is a customer case that has already been resolved.I have some doubt
in the solution provided.The problem description is as follows:

A and C are on hiQ AS1
B is on hiQ AS2
B activates a CFNR to C.
A calls B that activates the call forward to C.

After the establishment of the call between A and C, the call flow shows
a new SDP negotiation on the initiative of the AS, based on re-Invite
towards A and C.This phase is not described in TISPAN specifications.

The REINVITE message is triggered from hiQ to full fill SDP
security/privacy requirements. In this call scenario, A calls B and after
ring timeout hiQ forwards the call to "C".

In this initial call setup (A->B) A already shared its SDP information with
"B" and after the time out hiQ forwards the same A side SDP to "C"
subscriber. To full fill the security requirements, once the A and "C" are
connected hiQ sends a REINVITE without SDP to "C", forces it to generate a
new SDP and then forwards that SDP (received from "C") to "A" and forces
"A" to use a different SDP information than the original one which is
already shared with "B".

Is it possible to choose not to full fill the security requirements ?

Thanks and Regards,
Shaily Singh

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