[SIPForum-discussion] Hi

[Surya Prakash Ummadi]

Hi,

   please comment below  following  answers :


1) BRANCH and CSeq parameters will get change for every transaction?
>
> >> Yes.(this is correct)
>
>2) How Ack is treated as one transaction if the final response is 200-ok
>for
>    an INVITE?
>
> >> Yes. But it is a unique transaction and it's cseq is same as
>INVITE-200OK. Just the branch-identifier is different.
>
>3) How to detect loops and overcome them?
>
> >> For detecting loops ,branch-id is used as the reference.Branch-id is formed by the magiccooke and hash of the request-uri,from tag,totag ,cseq,callid and topmost VIA header.IF it is not the loop,atleast request-uri will change.So branch-id will be different.IF it same,then loop is detected.

Another way is MAX-Forwards.
>
>And also please mension/attach the docs if you have for my referrence.

  refer to the tech-invite site,where u can find good presentation of documents.
>
On Fri, 30 Mar 2007 Singh,Indresh(SNL US) wrote :
>
>

regards
surya
>-----Original Message-----
> From: discussion-bounces at sipforum.org
>[mailto:discussion-bounces at sipforum.org] On Behalf Of Taduru Hariprasad
>Sent: Friday, March 30, 2007 5:20 AM
>To: discussion at sipforum.org
>Subject: [SIPForum-discussion] Hi
>
>Hi,
>
>I started to learn sip. Currently going thru rfc 3261. Can i have th
>answers for the
>following doubts.
>
>1) BRANCH and CSeq parameters will get change for every transaction?
>
> >> Yes.
>
>2) How Ack is treated as one transaction if the final response is 200-ok
>for
>    an INVITE?
>
> >> Yes. But it is a unique transaction and it's cseq is same as
>INVITE-200OK. Just the branch-identifier is different.
>
>3) How to detect loops and overcome them?
>
> >> By checking if the ipAddress of your box is there in one of the i/c
>via headers. But after this you have to differentiate between loop and
>spiraling before you can say loop detected.
>
>And also please mension/attach the docs if you have for my referrence.
>
> >> Everything in RFC-3261 :)
>
>Thanks
>Hari
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