So the 'automaton' used in examples in RFC 5359 and RFC 7088 should be 'automata', right? I had thought that 'automaton' might be specified in some other RFC that I failed to locate.
Thanks! ------------------ Original ------------------ From: "Paul Kyzivat";<[email protected]>; Date: Wed, Apr 30, 2014 00:20 AM To: "ankur bansal"<[email protected]>; "SIP Learner"<[email protected]>; Cc: "sip-implementors"<[email protected]>; Subject: Re: [Sip-implementors] A question about the automaton feature tag On 4/29/14 10:42 AM, ankur bansal wrote: > sip.automata and automata represents same thing i guess That is arguable. The situation is somewhat complex. At the time RFC3840 was being written somebody saw a similarity between the tags being defined for it and feature tags that had been previously defined for unrelated purposes. And also that the definition of feature tags had defined matching rules. So it was decided to reuse the existing definitions and mechanisms for feature tags. (In retrospect I think this was an error, but nevertheless that is what was done.) The callerprefs mechanism (RFC3841) that operates in proxies is generic - it operates the same for all feature tags, and it is important that proxies be able to do it even for features unknown to them. As a result, it must be possible for a proxy to distinguish header field parameters that are feature tags (caller prefs or callee capabilities), from parameters that serve some other purpose. For that reason the "+" prefix was introduced to identify parameters that are being used as feature tags. BUT, drafts of callerprefs had been in progress for years, and there was a desire to preserve some backward compatibility for those who had implemented to those drafts. (In retrospect this was probably also a mistake.) So the set of sip feature tags that had been in the draft were designated "base tags". These are *special*, and are grandfathered. They are to be used without the leading "+sip." even though they are defined in the "sip tree" of feature tags. The text also *allows* the base tags to be used with a "+sip." or even "sip." prefix. Any other feature tags that are used MUST use the "+" prefix and the full name of the tag including the prefix for the tree it falls within. > Either its set as sip.automata=true/false OR automata(true by default) The following would all be ok: automata automata=true automata=false +sip.automata +sip.automata=true +sip.automata=false sip.automata sip.automata=true sip.automata=false Thanks, Paul > Feature parameter(not feature tag) can be added to Contact header by > UA(mostly some answering machine/voicemail server/IVR/announcement > server ) with value true or false > True : Call handled by answering > machine/voicemail server/IVR/announcement server > False : Call handled by human. > Mostly its seen when some server sends INVITE and add in Contact header . > Also this can be used in Register Contact header like sip.automata=false > to refuse to communicate with automation server . > > Thanks & regards > Ankur Bansal > > > > > On Tue, Apr 29, 2014 at 8:05 PM, SIP Learner <[email protected] > <mailto:[email protected]>> wrote: > > Thanks Paul! > > > At first I thought automaton as a typo too, but I found out that the > most recent RFC7088 also use automaton instead of automata, that's > why I asked the question. > > > > > > > > > ------------------ Original ------------------ > From: "Paul Kyzivat";<[email protected] > <mailto:[email protected]>>; > Date: Tue, Apr 29, 2014 08:35 PM > To: "sip-implementors"<[email protected] > <mailto:[email protected]>>; > > Subject: Re: [Sip-implementors] A question about the automaton > feature tag > > > > I presume "automaton" is simply an error - a misspelling. > You can look in the iana registry for all the defined feature tags. > > On 4/29/14 3:27 AM, SIP Learner wrote: > > Hi, guys! > > > > > > I am reading RFC5359 for SIP services examples, some of the > message examples contain a Contact header parameter like the following: > > > > > > Contact: <sips:[email protected] > <mailto:sips%[email protected]>>;automaton > > ;+sip.byeless;+sip.rendering="no" > > > > > > > > FRC5359 states that the automaton feature tag is defined in > RFC3840, but RFC3840 actually defined sip.automata instead of automaon. > > > > > > What is the difference between automaton and sip.automata anyway? > Are they equivalent or are they different? > > > > > > Thanks a lot! > > _______________________________________________ > > Sip-implementors mailing list > > [email protected] > <mailto:[email protected]> > > https://lists.cs.columbia.edu/mailman/listinfo/sip-implementors > > > > _______________________________________________ > Sip-implementors mailing list > [email protected] > <mailto:[email protected]> > https://lists.cs.columbia.edu/mailman/listinfo/sip-implementors > . > _______________________________________________ > Sip-implementors mailing list > [email protected] > <mailto:[email protected]> > https://lists.cs.columbia.edu/mailman/listinfo/sip-implementors > > _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/mailman/listinfo/sip-implementors
