[SIPForum-discussion] Prack

[pradeep p]

Hi Vijay,

I totally agree with your point that branch parameter is the parameter to
identify a transaction. In the above context, I just wanted to highlight the
significance of CSeq as it serves as a way to identify and order the
transactions. In your example also, we can see that the CSeq (sequence
number and method name) is different for INVITE and PRACK and hence, it is
also a way to identify the transaction.

Regards,
Pradeep P
PS: Refer 8.1.1.5 from rfc 3261.

On Tue, May 18, 2010 at 1:20 PM, Vijay Tiwari <vijay11tiwari at gmail.com>wrote:

> Yes, PRACK will be a new transaction and it will be identity by Vai branch
> parameter. please find the below logs for the same
>
>
>  SIP/2.0 183 Session Progress
> Via: SIP/2.0/UDP 8.19.19.06:5060;branch=z9hG4bK4545
> From: <sip:filo.farnsworth at television.tv<sip%3Afilo.farnsworth at television.tv>
> >;tag=12
> To: <+12025551313 at gw.carrier.com;user=phone>;tag=37
> Call-ID: 49235243082018498 at television.tv
> CSeq: 1 INVITE
> RSeq: 08071
> Contact: <sip:50.60.70.80>
> Content-Type: application/sdp
> Content-Length: 139
>
> v=0
> o=Port1723 2890844535 2890844535 IN IP4 50.60.70.80
> s=-
> t=0 0
> c=IN IP4 50.60.70.80
> m=audio 62002 RTP/AVP 0
> a=rtpmap:0 PCMU/8000
>
>
>
>
>  PRACK sip:50.60.70.80 SIP/2.0
> Via: SIP/2.0/UDP 8.19.19.06:5060;branch=z9hG4bK454
> Max-Forwards: 70
> From: <sip:filo.farnsworth at television.tv<sip%3Afilo.farnsworth at television.tv>
> >;tag=37
> To: <sip:+12025551313 at gw.carrier.com <sip%3A%2B12025551313 at gw.carrier.com>
> ;user=phone>;tag=12
> Call-ID: 49235243082018498 at television.tv
> CSeq: 2 PRACK
> Contact: sip:filo.farnsworth at studio.television.tv<sip%3Afilo.farnsworth at studio.television.tv>
> RAck: 08071 1 INVITE
> Content-Length: 0
> both Branch id are different
>
>
> thanks
> vijay
> On Fri, May 14, 2010 at 10:27 AM, Dileep Ravindran <
> dileepravindran at tataelxsi.co.in> wrote:
>
>>  Hi All,
>>
>>    Can anyone please tell whether  PRACK  a new transaction?? and if yes
>> which  parameter that tells that its a new transaction??
>> \Thanks
>> Dileep
>>
>>
>>
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>
>
> --
> They can because they think they can.
>
>
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