Folks, It is with great pleasure that I announce the availability of draft-ietf-sip-rfc2543bis-05. Until it appears in the archives, you can pick it up at:
http://www.jdrosen.net/papers/draft-ietf-sip-rfc2543bis-05.txt http://www.jdrosen.net/papers/draft-ietf-sip-rfc2543bis-05.ps http://www.jdrosen.net/papers/draft-ietf-sip-rfc2543bis-05.pdf As most of you are aware of, this version represents a substantial rewrite of the specification. As the spec has evolved over time, text was added in here or there, and the spec grew inconsistent and hard to read. The aim of this rewrite was to make vast improvements on both the conciceness and completeness, and the readability, of the specification. This was no small task, and it was clear that we would need help. So, a "bis editor" team was formed. In addition to Henning and myself, we added four new co-authors to the specification: Robert Sparks, Alan Johnston, Jon Peterson, and Gonzalo Camarillo. Dean and Brian assisted in editing and guidance, Rakesh provided project management, and a dynamicsoft technical writer, Jean Mahoney, was brought in to work the text (although her edits will not reflect until -07). I prepared a new structure for the specification, and the team began to busily write. We held conference calls at least once a week throughout September and October, and iterated on the specification five times before the version above was produced. We even went through the immensely painful task of tracking every single MUST/MAY/SHOULD in bis-04 to make sure nothing was lost. The team did a phenomenal job, and was really dedicated to making this happen in a reasonable time frame. Great work, team! If I had to summarize the nature of the change, I would do so in two ways. First, the new spec is "semantically oriented" instead of "syntactically oriented". That is, instead of focusing on the syntax, and descirbing behavior as a side product of headers and methods, the specification focuses on behaviors, and describes the syntax needed for it. For example, we now have sections specifically dedicated to initating a session (you'd think there would be a section on that in a specification called "session initiation protocol"), modifying a session, and terminating a session. There is a section that describes registrar behavior from the receipt of a REGISTER to the sending of a response. As part of this change, the BNF was collected into one place, and put in the end. We also took the time (Brian did most of this work) to convert from implicit to explicit LWS. The headers section has shrunk tremendously, as most of the normative behavior was moved forward to sections that describe the main operations in SIP. The second big change was to add layering to SIP. Most of us who know sip well have recognized its layering, but it is not clear at all from the presentation. Now, there is an explicit transport layer and transaction layer. UA processing is defined as a UA "core" layer that sits ontop of the transaction and transport layers. We have unified transaction processing between proxies and UAs, so that there is a single set of state machines for trnsaction processing in all elements. Doing so required a somewhat radical change in structure; reliability of the 2xx response to INVITE, and the ACK for 2xx, is no longer handled by the transaction layer. Rather, its done in the UA core. There are now provably terminating state machines for all four transaction types - INVITE and non-INVITE client and servers. The transaction machines have been made transport independent by reverting to timers for many transitions, rather than retransmit counts. As part of the effort to improve readability, there is a lot more tutorial material. Included is a badly needed four page SIP overview up front, with increasing details at the front of subsections as you move through the document. We've also structured it to be top down. Details are towards the end of the spec, basics up front. As a shocker to the PSTN community, the term "call leg" has been eradicated from the specification with prejudice. The reason is that we are using call legs for things like subscriptions, which have nothing to do at all with calls. The new term is "dialog". At the direction of the ADs, I have also incorporated draft-ietf-sip-serverfeatures into bis. In a future revision, the reliability of provisional responses (draft-ietf-sip-100rel) will be incorporated as well. For now, there is a placeholder for it to give people a heads up. Another big change was the extraction of SDP processing into a separate document. The offer/answer model was submitted as a personal I-D, which should appear in the archives soon. Until it does, you can grab a copy at: http://www.jdrosen.net/papers/draft-rosenberg-mmusic-sdp-offer-answer-00.txt This has changed little from bis-04. The main change is how hold is done, based on list consensus. I also added discussion of the ptime attribute. THe bulk of the change in the spec itself is the presentation and rewrite. However, there are, of course, some functional changes in the protocol itself. We have tried to capture as much as we could in the changes section for draft-05. However, I am certain that there are things that were lost or added or changed that we missed. Please keep an eye out, and feel free to point things out on the lists. And definitely read that changes section. This draft is not the end of the rewrite; its just the first major milestone. We now need to get extensive reviews made of it, to verify its correctness and its readability. Over the next few weeks, we'll be collecting and integrating those comments and reviews, with the intent of issuing bis-06 in a few weeks time. So, please take a look and send your comments! I and the other co-authors will be monitoring the lists more closely than usual to answer questions (my unusual absence on the list over the past months has been entirely due to working on bis...) Thanks, Jonathan R. --- Jonathan D. Rosenberg, Ph.D. 72 Eagle Rock Ave. Chief Scientist First Floor dynamicsoft East Hanover, NJ 07936 [EMAIL PROTECTED] FAX: (973) 952-5050 http://www.jdrosen.net PHONE: (973) 952-5000 http://www.dynamicsoft.com _______________________________________________ Sip-implementors mailing list [EMAIL PROTECTED] http://lists.cs.columbia.edu/mailman/listinfo/sip-implementors
