I agree that a REFER message is better than a B2BUA for 3rd party call-control. For example, a B2BUA can not guess the SIP methods (of Allow header) and SIP option-tags (of Supported & Required headers) of the 2nd party when sending the first INVITE to the 1st party.
> Not all UAs support REFER. Unfortunately, this is especially true in SIP-PSTN gateways. _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
