From a usage point of view, it is far more useful to model REFER as
if it were a SUBSCRIBE request.
It creates a subscribe usage if it succeeds.
The impact it has on the invite usage if it fails is the same as if a
FOO request failed (which depends on the failure).
RjS
On Mar 23, 2009, at 5:07 PM, Dale Worley wrote:
On Mon, 2009-03-23 at 08:18 -0700, Brett Tate wrote:
Everyone: Is REFER within dialog part of INVITE usage, SUBSCRIPTION
usage, or neither?
I'm asking mainly because of REFER 481 impacts; however the answer
also has potential implications concerning draft-ietf-sip-info-
events.
RFC 5057 appears to imply that it is part of the subscription usage;
however I'm not positive if my interpretation and/or RFC 5057 is
correct.
If REFER isn't considered part of the INVITE usage, how should REFER
481 be interpreted? More specifically, should receiver of REFER 481
send BYE?
I would argue that the REFER is part of the INVITE usage, because
REFER
in that context is intimately related to the INVITE usage -- it is
intended to transfer the INVITE usage/dialog transferred to a
different
destination.
And it seems quite safe that if the REFER receives a 481 response, the
INVITE usage must not be functional any more, since the far end of
that
usage has denied that it can act on the REFER.
Now it's possible that the REFER, if it is successful, is the first
transaction of the subscription usage. But I don't think that has any
paradoxical consequences, as by hypothesis, the REFER succeeded.
Dale
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_______________________________________________
Sip mailing list https://www.ietf.org/mailman/listinfo/sip
This list is for NEW development of the core SIP Protocol
Use [email protected] for questions on current sip
Use [email protected] for new developments on the application of sip
