[SIPForum-discussion] LOOP CALL

[vijay kant gupta]

I'll give you an example. in which Redirect server fwd the invite to
location server and Location server agin fwd to redirect server.. this the
one of condition inwhich Spiral is used.

On Thu, Aug 21, 2008 at 3:33 AM, Raghul Prasanna <raghul82 at yahoo.co.uk>wrote:

> 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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