Re: [Sip] ACK not matching

["Dale Worley" <dworley at nortel.com>]

On Wed, 2008-12-10 at 16:39 +0530, sunil.bhagat at wipro.com wrote:
> Is it correct to have “user=phone” added only in ACK’s To header while
> it is missing in initial INVITE, even though both the messages use
> Tel-URI.

The matter is not well-settled by the standards.  RFC 3261 requires the
UAs to not change the To/From URIs in requests they generate, but it
also requires that UAs not look at the To/From URIs that they receive,
only the tags (except in certain special circumstances).

Some proposed changes and uses of SIP require the To/From URIs to be
changed.

So the current best practice is (1) Never depend on the To/From URIs in
incoming messages to be the same as in the initial INVITE, only pay
attention to the tags, and (2) Only change the To/From URIs in specific
situations where you absolutely must do so.

In this case, there is no reason why the ACK To/From URIs differ from
the INVITE values (indeed, it's hard to think of any reason it could
be), so "user=phone" should not be added.

Dale


_______________________________________________
Sip mailing list  https://www.ietf.org/mailman/listinfo/sip
This list is for NEW development of the core SIP Protocol
Use sip-implementors at cs.columbia.edu for questions on current sip
Use sipping at ietf.org for new developments on the application of sip