[SIPForum-discussion] LOOP CALL

[Raghul Prasanna]

Hi Vijay,
 
  what is the use of spiral method?
 
thanks,
Raghul

--- On Wed, 20/8/08, vijay kant gupta <vijaykant.it2002 at gmail.com> wrote:

From: vijay kant gupta <vijaykant.it2002 at gmail.com>
Subject: Re: [SIPForum-discussion] LOOP CALL
To: "Mishra2, Abhishek (NSN - IN/Bangalore)" <abhishek.mishra2 at nsn.com>
Cc: discussion at sipforum.com
Date: Wednesday, 20 August, 2008, 8:01 PM



There are two case in sip.
first is loopback that is an error. In this Scenario. the A party send to proxy now proxy has to fwded B party but proxy fwded itself without change in via method.
Second is Spiral method in A party  fwd to proxy but proxy change in via method  to itself.
spiral is not an error.


On Wed, Aug 20, 2008 at 11:01 AM, Mishra2, Abhishek (NSN - IN/Bangalore) <abhishek.mishra2 at nsn.com> wrote:

Hi Nitin

 The  Requests that arrive at a proxy, is forwarded  and later arrives
back at the same proxy are treated as loop requests provided:
(a) Via header branch parameter value matches to previous requests by
the proxy

SIP provides following mechanism for loop detection and prevention:
MAX-Forwards
========
(i) Counter decremented by 1 on every hop
(II) Discard request when it is zero

VIA
===
(i)  Every proxy inserts an address
(ii) Check for my address (proxy address) when the request comes


Loop requests are errors

Hope that this helps

Bye
Abhishek




-----Original Message-----
From: discussion-bounces at sipforum.org
[mailto:discussion-bounces at sipforum.org] On Behalf Of ext nitin kapoor
Sent: Wednesday, August 20, 2008 3:44 AM
To: discussion at sipforum.com
Subject: [SIPForum-discussion] LOOP CALL

Hello Everyone

I just wants to know  about the LOOP CALL. what does it mean. Why we are
using this.

Please let me know because i wants to know ASAP.

Regards
Nitin Kapoor
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