[SIPForum-discussion] c-seq value in SIP call

[Ruben Roque]

Hi Murali,

Cseq is used for the following purpose:
1) It serves as a way of ordering requests and responses in a dialog.
2) The RFC also talks of Cseq as being used to identify a transaction.
Although branch parameter in VIA takes care of identifying transactions, I
am not sure how Cseq helps in identifying a transaction -- U will need to
confirm this.

It only increments for each new request within a dialog. As mentioned in
your below mail, the BYE request has a Cseq of 2 because it is a new request
within a dialog and hence it is incremented.


Kindly get back to me incase of any queries.


Thanks and Regards,
Reuben Decruz


On Mon, Oct 25, 2010 at 10:12 PM, murali shankar <murali.elangovan at gmail.com
> wrote:

> Hi All,
>
> Please explain me the below
>
> 1.What is the use of c-seq in a SIP call ?
> 2.I Have observed that in all the cases the values is 1 except when it
> sends the bye request[it is giving cseq ID:-2]
> 3.In what are all the cases the c-seq value will get chaged?
>
> --
> Thanks & Regards,
> Murali Shankar.E
>
>
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