Document: draft-ietf-sip-hitchhikers-guide-03 Reviewer: Avshalom Houri [AVSHALOM@il.ibm.com] Review Date: 10/29/2007 Review Due: 10/29/2007 Review Type: WGLC (SIMPLE perspective) Summary: In my opinion this draft is basically ready for publication, but has nits that should be fixed before publication. Citations from the draft are marked by <<< text from draft >>> General comments ---------------- By its nature there are a lot of reference to drafts in the document. It will take a lot of time for these documents to become and RFC. So how we are going to publish this as an RFC? Since when the referenced drafts will become an RFC, this draft would have to be updated with new drafts, will it be held in the RFC ED queue for ever? How do we gauge the usage of an RFC or a draft? There are many places here that it is said that this or that RFC/draft got widely implemented or not. How it is measured? The wide implementation test is used to decide whether an RFC or draft are core or not and therefore there should be some text explaining how the wide implementation was determined. Better change RFC XXXX (before the reference number in []) to the name of the draft (with no version number), it will make the ride smoother. An introduction that details the various grouping should be added. It should include additional text on the group and what was the criteria for putting an RFC/draft in the group. 2. Scope of this Document -------------------------- <<< o Any specification that defines an extension to SIP itself, where an extension is a mechanism that changes or updates in some way a behavior specified in RFC 3261 >>> "to SIP itself" sounds vague. It will be better to say:"to RFC 3261" instead. Maybe there should be an earlier definition of RFC 3261 as the SIP nucleus (or the president of the galaxy) and that RFCs/drafts mentioned in this document are based on their relation to it. <<< Excluded from this list are requirements, architectures, registry definitions, non-normative frameworks, and processes. Best Current Practices are included when they normatively define mechanisms for accomplishing a task. >>> "normatively define" not sure what is meant by normative with respect to BCP. Seems like a contradiction in terms. 3. Core SIP Specifications --------------------------- If we think on presence as eventually replacing registration, since it carries much more information about the availability of the user, should we consider also presence as a towel? <<< RFC 3261, The Session Initiation Protocol (S): RFC 3261 [1] is the core SIP protocol itself. RFC 3261 is an update to RFC 2543 [9]. It is the president of the galaxy [42] as far as the suite of SIP specifications is concerned. >>> RFC 3261 is a very big document. Should it be treated as one or it can be divided into parts in this document e.g. proxy, client etc.? I am not sure what would be better. 4. Public Switched Telephone Network (PSTN) Interworking --------------------------------------------------------- Regarding RFC 3578 Ugly in one corner of the galaxy may be beautiful on the other of it :-) 7. Minor Extensions -------------------- <<< RFC XXXX, Referring to Multiple Resources in SIP (S): RFC XXXX [44] allows a UA sending a REFER to ask the recipient of the REFER to generate multiple SIP requests, not just one. This is useful for conferencing, where a client would like to ask a conference server to eject multiple users. >>> Should not this be referred to in the conferencing section also? <<< RFC 4483, A Mechanism for Content Indirection in Session Initiation Protocol (SIP) Messages (S): RFC 4483 [89] defines a mechanism for content indirection. Instead of carrying an object within a SIP body, a URL reference is carried instead, and the recipient dereferences the URL to obtain the object. The specification has potential applicability for sending large instant messages, but has yet to find much actual use. >>> The specification has also potential for sending large presence documents via a URL. <<< RFC 4583, Session Description Protocol (SDP) Format for Binary Floor Control Protocol (BFCP) Streams (S): RFC 4583 [91] defines a mechanism in SDP to signal floor control streams that use BFCP. It is used for Push-To-Talk and conference floor control. >>> Should not this be referred to in the conferencing section also? <<< RFC XXXX, Connectivity Preconditions for Session Description Protocol Media Streams (S): RFC XXXX [93] defines a usage of the precondition framework [59]. The connectivity precondition makes sure that the session doesn't get established until actual packet connectivity is checked. >>> Should not this be referred to in the QoS section also? 8. Conferencing ---------------- The Conferencing section should be before or after "Instant Messaging, Presence and Multimedia" as it is also an application. See the comment on whether presence is an application or not later. 10. Event Framework and Packages ---------------------------------- Suggest to divide this section to event framework section and to packages section. The event framework should include 3265, 3903, 4662 and subnot-etags which define the event framework itself. The other section will the packages sections that will list the packages. Alternatively, many of the packages are mentioned in their proper section so it may be that all the event packages can be fit into their relevant section and there is not a need for packages section. 11. Quality of Service ----------------------- <<< RFC 3313, Private SIP Extensions for Media Authorization (I): RFC 3313 [61] defines a P-header that provides a mechanism for passing an authorization token between SIP and a network QoS reservation protocol like RSVP. Its purpose is to make sure network QoS is only granted if a client has made a SIP call through the same providers network. This specification is sometimes referred to as the SIP walled garden specification by the truly paranoid androids in the SIP community. This is because it requires coupling of signaling and the underlying IP network. >>> Understand that being a "truly paranoid" is a virtue? :-) 15. Security Mechanisms ------------------------ Should not RFC 3323 (Privacy), RFC 3325 (Asserted-ID) and RFC 4474 (Identity) be mentioned here also? 16. Instant Messaging, Presence and Multimedia ----------------------------------------------- Maybe create an applications section and put also conferencing as a type of an application. Including presence here with IM and multimedia seems that presence is regarded as an additional type of media. I am not sure that I agree with this. Presence is an enabler for many other applications and it deserves a section of its own. It is very tempting to include the simple-simple content here (as an appendix?). If simple-simple is not to be included here, there should be at least a reference to simple-simple as for presence there are so many documents that are essential for doing presence and are not mentioned here (e.g. watcher format, RPID, presence rules, partial notify and publish and many many more). Roughly counting, there are about 20-25 RFCs/drafts that are very relevant to presence that are mentioned in simple-simple in addition to the ones that are mentioned here. The MSRP drafts seem to be forgotten?