Hi, Sorry; I misinterpreted "The ultimate reason" paragraph. However, the same comments apply.
My understanding is that you can't be certain about how it will be handled without the use of user-parameter (or local restrictions on the name space) to know how to decode the user portion of the sip-uri. RFC 3966 appears to allow adding optional parameters without it causing a problem. Thus if you add "user=phone" as sip-uri parameter, things will likely work. I don't recall how RFC 4967 treats unknown parameters when "user=dialstring". > -----Original Message----- > From: sa...@allegro-1.evaristesys.com [mailto:sasha@allegro- > 1.evaristesys.com] On Behalf Of Alex Balashov > Sent: Friday, November 04, 2016 9:57 AM > To: Brett Tate; sip-implementors@lists.cs.columbia.edu > Subject: Re: [Sip-implementors] Semantics of parameters in URI username > > Brett, > > Thank you for your answer, but it is still rather clear—likely to my > feeble > intellect—how to apply this to my question about use of Diversion to pass > state. > > On 11/04/2016 07:04 AM, Brett Tate wrote: > > >> As far as I can tell from the RFC 3261 ABNF, it is permitted to put > >> SEMI and EQUAL in the username of a URI, but it has no semantic > >> validity. > > > > The user-parameter can help. However, be aware that some vendors add > > "user=phone" when user portion is absent or otherwise cannot be > > decoded as telephone-subscriber. > > > > RFC 3261 section 19.1.1: > > > > "If the user string contains a > > telephone number formatted as a telephone-subscriber, the user > > parameter value "phone" SHOULD be present. Even without this > > parameter, recipients of SIP and SIPS URIs MAY interpret the pre-@ > > part as a telephone number if local restrictions on the name space for > > user name allow it." > > > > Concerning your RFC 4694 example, see RFC 3261 section 19.1.6 > > concerning how to convert a tel URL into SIP URI. > > > >> So, how does that work? Is the voodoo that gives username-embedded > >> parameters meaning embedded somehow in the complex rules governing > >> the conversion of 'tel:' scheme URIs to 'sip:'? Or am I mistaken in > >> my assumption that parameters cannot be embedded in the user part of > >> a URI to begin with? > > > > The "user=phone" can be added to avoid the ambiguity. _______________________________________________ Sip-implementors mailing list Sip-implementors@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/sip-implementors
