On Nov 20, 2008, at 10:45 PM, Elwell, John wrote:
Dean,-----Original Message----- From: Dean Willis [mailto:dean.willis at softarmor.com] Sent: 20 November 2008 23:16 To: DRAGE, Keith (Keith) Cc: Christer Holmberg; Paul Kyzivat; SIP List; Elwell, John Subject: Re: [Sip] INFO Framework: Tags No, you use the options tag with a sip.extensions media feature tag ala RFC 3840 in order to get a retargeting proxy to send the request only to the subset of UAS that support the extension.[JRE] RFC 3841 does not compel a proxy to behave in this way, and in fact the proxy might not even support RFC 3841.
RFC 3840/3841 can insure such behavior, and (with Proxy-require) can assure that the proxy either supports the extension or rejects the call.
So you have to be prepared for your INVITE/Recv-Info to go to any UAS.
well, it MIGHT do so, and fail in a predictable way as a consequence due to the Require: info-package. That's not a bad thing.
I don't in generalsee a need to specify this as part of the extension in general, but if aparticular package needs a feature tag, let it define one. Keep the extension simple.
Only standards-track RFCs can define SIP option tags under RFC 3427, and we have no plans to relax this requirement.
But we have a much looser policy for INFO packages; most will not be standards-track.
So, for those sorts of packages, an info-package option tag is potentially quite useful.
-- Dean _______________________________________________ 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