Hi Catillo, Some comments marked [Krishna] inline.
Regards Krishna > Message: 6 > Date: Mon, 15 Sep 2008 17:31:36 +0200 > From: " I?aki Baz Castillo " <[EMAIL PROTECTED]> > Subject: Re: [Sip-implementors] question regarding REGISTER - RFC 3665 > Cc: [email protected] > Message-ID: > <[EMAIL PROTECTED]> > Content-Type: text/plain; charset=UTF-8 > > 2008/9/15, krishna kalluri <[EMAIL PROTECTED]>: > > Hi, > > > > I have a question related to the usage of Call-Id and CSeq header > fields. > > > > I take the examples in section 2 of RFC 3665 ( > > http://tools.ietf.org/html/rfc3665) and I consider the examples as a > > sequence of messages exchanged by a UE. So different messages in section > 2.1 > > through 2.4 are exchanged one after the other (This may not be what RFC > 3665 > > wants to show and thats fine with me) > > I think that RFC 3665 shows a correct sequential SIP flow. Anyway it > could use different Call-ID/CSeq (but the flow is valid). [Krishna] If the RFC assumes correct sequence flow then Section 2.4 should have CSeq = 2. > > > > > 1) 2.2 Update of a contact List (RFC 3665) : The CSeq number is same as > in > > example 2.1. If I understand this is fine as UE is adding a new contact > > binding. > > I think so since: > > 10.3 (7): > > Each binding record records the Call-ID and CSeq values from > the request. > > This is: Call-ID and CSeq are correlated for *each* binding. No matter > if same Call-ID/CSeq is used for a different binding. > > > > If I make an example of refreshing contact list, does CSeq MUST be > higher > > than the previously used CSeq? I guess so from Step 7 of Section 10.3 of > RFC > > 3261. > > I think so: > > If they (Call-ID) are > the same, the registrar compares the CSeq value. If the value > is higher than that of the existing binding, it MUST update or > remove the binding as above. If not, the update MUST be > aborted and the request fails. > > > > > 2) 2.4 Cancellation of Registration (RFC 3665): In this case CSeq number > > MUST be greater than the one used in previous messages. This is from my > > interpretation from Step 6 of Section 10.3 of RFC 3261. > > But that is needed just if "Contact" matches a binding, but note that > the "Contact" in 2.4 is: > Contact: * > [Krishna] Step 6 of Section 10.3 of RFC 3261 is describing about Contact = * scenario. > > > > 3) Does a UE use same Call-Id value in all Register messages? or is > there > > any case where it has to change Call-Id value? > > I think a UAC has no reason to use a new Call-ID. But this can occur > due to UAC crash (for example) so it's needed an algorith to handle > this case. If a new REGISTER arrives to the registrar matching a > binding but with different Call-ID then the previous binding is > deleted (this can occurs because the client crashed). > > > Regards. > > > > > > -- > I?aki Baz Castillo > <[EMAIL PROTECTED]> > > > > ------------------------------ > > _______________________________________________ > Sip-implementors mailing list > [email protected] > https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors > > End of Sip-implementors Digest, Vol 66, Issue 26 > ************************************************ > _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
