Re: [reSIProcate] Lack of Contacts field in SIP header does not Create dialog
Check out section 12 of RFC3261. The Contact header IS required to form a dialog, even though it is not part of the Dialog Id. I don't think this change is a good idea. Typically the contact header needs to identify the exact IP and port to the other party for routing of mid dialog requests. The To header does not contains this level of information, it contains the AOR only.
RFC text:
The UAS MUST add a Contact header field to
the response.
When a UAC sends a request that can establish a dialog (such as an
INVITE) it MUST provide a SIP or SIPS URI with global scope (i.e.,
the same SIP URI can be used in messages outside this dialog) in the
Contact header field of the request.
The remote target MUST be set to the URI
from the Contact header field of the response.
Scott