The language in RFC 3840 doesn't appear to contemplate the situation you've proposed. In its world, registrars can either support prefs (and will accept "Require: pref") or they don't, and they don't have knowledge of which feature tags are registered with IANA and which are not. Of course, they *coud* attempt to validate the tags expressed by the UA, but I don't see an explicit way for the registrar to indicate that the UA included disallowed tags in its request.
_______________________________________________ Gen-art mailing list [email protected] https://www.ietf.org/mailman/listinfo/gen-art
