Subject: Re: [Sipping] Question on RFC 3725 (3PCC)

From: "Dale Worley" <[email-masked]>
Date: Thu, 5 May 2005 09:57:48 -0400

From: Elwell, John [[email-masked]]

> I have a concern about the working of 3PCC when an SDP offer is rejected.
>
> In flow 1, what if the SDP offer from A is rejected by B? B will send a
488
> response to the controller, but this cannot be relayed back to A.
Presumably the
> only action that the controller can do is to send an ACK to A (but that
should
> contain an SDP answer, so how is it populated?) and then a BYE to A. A
will
> never receive the reason for failure. In particular, if the reasons for
failure
> was the rejection of key management for payload encryption, A cannot retry
> (e.g., without payload encryption). Of course, the controller can retry,
but it
> will probably yield the same result.

The difficulty of doing SDP negotiation well is one reason to avoid this
sort of "back-to-back user agent" schemes.

Dale

_______________________________________________
Sipping mailing list  https://www1.ietf.org/mailman/listinfo/sipping
This list is for NEW development of the application of SIP
Use [email-masked] for questions on current sip
Use [email-masked] for new developments of core SIP