El Miércoles, 1 de Octubre de 2008, Victor Pascual Ávila escribió: > RFC3261 > 20.32 Require > The Require header field is used by UACs to tell UASs about options > that the UAC expects the UAS to support in order to process the > request. > > RFC4028 > 8.1. Processing of Requests > the proxy MAY insert a Require header field with the value 'timer' > into the request. > > Is a SIP proxy allowed to insert Option tags when forwarding a > request? In that case, why "Require" is preferred than "Supported" in > RFC4028?
I don't understand how a proxy can add a "Require" option tag. Let me explain the issue with an example: - A sends INVITE to B through proxy P. - P adds "Require: xxxx". - B replies "420 Bad Extension". - "420" arrives to P who forwards it to A. - So A receives the "420" with a header "Unsupported: xxxx". - A didn't add that option tag so it doesn't understand what happened. IMHO a proxy CANNOT add a Require option tag, can it? -- Iñaki Baz Castillo _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
