[SIPForum-discussion] How to use lr parameter in URI

[harish T]

Thank you Hemanth,

case 2: (Based on your explanation ,Can i conclude like this )

 if second URI contain lr parameter then
 <sip:proxy1>,<sip:proxy2;lr>,<sip:proxy3>,<sip:proxy4>,<sip:user at remoteua>

For 2nd hop will this request formate correct

METHOD <sip:user at remoteua>(removing 2nd URI from Record route,and placing
end point info in Request URI)
Route: <sip:proxy3>,<sip:proxy4>,<sip:user at remoteua>

For 3rd  hop will this request formate correct

METHOD <sip:proxy3>
 Route: <sip:proxy4>,<sip:user at remoteua>






On 2/15/07, hemanth kumar <cyhk007 at yahoo.com> wrote:
>
> Hi
>
> Please find my answers inline
>
> *harish T <harish0611 at gmail.com>* wrote:
>
> While reading RFC 3261 i could not make out the difference between "URI that contain   the lr parameter" and
> "URI does not contain lr parameter"
>
> case 1:
>    if first URI doen't contain lr parameter then
>           <sip:proxy1>,<sip:proxy2>,<sip:proxy3;lr>,<sip:proxy4>
>
>    The request will be formed with the following Request-URI and Route
>    header field:
>
>    METHOD sip:proxy1
>      Route:
>  <sip:proxy2>,<sip:proxy3;lr>,<sip:proxy4>,<sip:user at remoteua>
>
> If the lr parameter is absent, it means that it is a strict router. Strict
> router expects its entry( that it added in the Record Route of the initial
> Request) in the Request URI. So the UA gets the entry from the route set and
> puts it in the Request URI. It adds the end point's info as the last entry
> in the record route.
>
> case 2: (is this correct?)
>
>  if first URI contain lr parameter then
>           <sip:proxy1;lr>,<sip:proxy2>,<sip:proxy3>,<sip:proxy4>
>
>    The request will be formed with the following Request-URI and Route
>
>
> header field:
>
> METHOD sip:proxy1
> Route: <sip:proxy2>,<sip:proxy3>,<sip:proxy4>,<sip:user at remoteua>
>
> Is this correct?...
>
> I could not understand the lr concept ...if any one knows please explain
> how to use lr parameter...
> if possible please provide simple example
> If the UA finds from route set that the next hop is a loose router, It
> then uses the end point's info (obtained from the contact header in the
> initial request) in the Request URI and sends it. when it reaches the loose
> router, it looks for its entry in the route set and removes its entry from
> the route list and forwards it to the next hop. Before forwarding it checks
> in the route set if the next hop is a loose router or a strict router. if it
> is a strict router, it replaces the Request URI with the next hops entry in
> the route list and removes that entry in the route list. It also adds
> the destination's entry from the request URI to the route set as the last
> entry.
> Hope this answers your question
> Regards
> Hemanth
>
>
>
>
> --
> ------------------------------------------------------
> To accomplish great things, we must not only act, but also dream; not only
> plan, but also believe.
>
>
>
> With regards
> Harish.T _______________________________________________
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>
>
>  *********************************************************************
> *Chenji Hemanth Kumar*
> Wipro Technologies
> Ph: 23404007
> *********************************************************************
>
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-- 
------------------------------------------------------
To accomplish great things, we must not only act, but also dream; not only
plan, but also believe.



With regards
Harish.T
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