[SIPForum-discussion] very imp question about route& recordroute

Sat Apr 28 09:52:33 UTC 2007

Hi Deepanshu,

Basically, the SIP signalling and the media do not traverse the same paths.

For instance in IMS, SIP signaling goes through the proxies (CSCF's), while
the media goes via the GGSN or SBC or MGW (depending on the network) and
proxies will not involved in processing media streams. (also not required)

By adding record_route header into the request, proxy ensures that
subsequent requests (for ex re-Invite) flow through it onceagain, again it
is SIP signalling not media.

In simple terms media flows between two clients directly, and proxy is
involved only in setting the session thro SIP signalling.

Hope this clariffies your doubts.

Reg
Balaji

On 4/28/07, Deepanshu <deepanshu at huawei.com> wrote:
>
>  I got it....
>
> But, can you give some reason to support your statement.
>
> When a proxy gets a request with route header and its a statefull proxy
> then it will insert a record_route header in the outgoing request. Due to
> that all the subsequent request will go through P1, which imply that P1 is
> in the media path.
>
> on the other hand...
>
>  When a proxy gets a request with route header and its a *stateless* proxy
> then it will *not* insert a record_route header in the outgoing request. Due
> to that all the subsequent request will *not* go through P1, which imply
> that P1 is *not* in the media path.
>
> So, i cannot understand or support your statemt like "*What i was saying
> is, P1 will not come into the media path*". Why P1 will not come in media
> path? it depends on the procedures what proxy adopts.
>
> hope i'm not missunderstanding you again
>
> *Deepanshu Gautam*
> R&D Engineer
> Huawei Technologies Co. Ltd.
> Nanjing Institute, No 91 BaiXia Rd.
> Nanjing, Jiangsu, P. R. China 210001
> Mobile: +86-13585147627
> Email: depanshu at huawei.com
>
>
> ----- Original Message -----
> *From:* gurudatt balaji <gurudattbalaji at gmail.com>
> *To:* Deepanshu <deepanshu at huawei.com>
> *Sent:* Friday, April 27, 2007 7:32 PM
> *Subject:* Re: [SIPForum-discussion] very imp question about route&
> recordroute
>
>
>
> ************************************************************************************************************************************
> yes, i think so............... P1 is a default proxy for user A
> to forward his request.
>
> request will contain the route header, *now if p1 wants to be in media
> path then it will record route*
>
> ************************************************************************************************************************************
> According to ur above statment,
>
> What i was saying is, P1 will not come into the media path"
>
>
> On 4/26/07, Deepanshu <deepanshu at huawei.com> wrote:
> >
> >  Sorry dear,
> >
> > i think i did not get you completely, are you trying to say that P1
> > cannot be in media path? (i hope not)
> >
> > ----- Original Message -----
> > *From:* gurudatt balaji <gurudattbalaji at gmail.com>
> > *To:* Deepanshu <deepanshu at huawei.com>
> > *Cc:* William Prusty <williamp at techmahindra.com> ;
> > discussion at sipforum.org
> > *Sent:* Wednesday, April 25, 2007 4:24 PM
> > *Subject:* Re: [SIPForum-discussion] very imp question about route&
> > recordroute
> >
> >
> > Hi Deepanshu,
> >
> > I donot think P1 comes in the media path, also record_route header
> > entries for subsequent requests (not media) within a dialog.
> >
> > Can u confirm.
> >
> > Reg
> > Balaji
> >
> >
> > On 4/25/07, Deepanshu <deepanshu at huawei.com > wrote:
> > >
> > >  yes, i think so............... P1 is a default proxy for user A
> > > to forward his request.
> > >
> > > request will contain the route header, now if p1 wants to be in media
> > > path then it will record route
> > >
> > > ----- Original Message -----
> > > *From:* William Prusty <williamp at TechMahindra.com>
> > > *To:* Deepanshu <deepanshu at huawei.com>
> > > *Sent:* Tuesday, April 24, 2007 5:12 PM
> > > *Subject:* RE: [SIPForum-discussion] very imp question about route&
> > > recordroute
> > >
> > >
> > >
> > > If P1 must be configured at   A ;s client , then every time the
> > > request generated by A will contains the route header field containing the
> > > address of P1
> > >
> > >
> > >
> > >
> > >
> > > Am I right?? Plz clarify
> > >
> > >
> > >  ------------------------------
> > >
> > > *From:* Deepanshu [mailto: deepanshu at huawei.com]
> > > *Sent:* Tuesday, April 24, 2007 2:34 PM
> > > *To:* William Prusty
> > > *Cc:* discussion at sipforum.org
> > > *Subject:* Re: [SIPForum-discussion] very imp question about route&
> > > recordroute
> > >
> > >
> > >
> > > P1 MUST be configured in A's client
> > >
> > >  ----- Original Message -----
> > >
> > > *From:* William Prusty <williamp at TechMahindra.com>
> > >
> > > *To:* Deepanshu <deepanshu at huawei.com> ; Srinivas .<nsrinivas at TechMahindra.com>
> > >
> > > *Cc:* discussion at sipforum.org
> > >
> > > *Sent:* Tuesday, April 24, 2007 11:52 AM
> > >
> > > *Subject:* RE: [SIPForum-discussion] very imp question about route&
> > > recordroute
> > >
> > >
> > >
> > > Thank u deepansu.
> > >
> > >
> > >
> > > If p1 is not configured in A "s client , then whether at that time A
> > > required help of DNS to find the address of p1.????
> > >
> > >
> > >
> > >
> > >  ------------------------------
> > >
> > > *From:* discussion-bounces at sipforum.org [mailto:
> > > discussion-bounces at sipforum.org] *On Behalf Of *Deepanshu
> > > *Sent:* Tuesday, April 24, 2007 7:23 AM
> > > *To:* Srinivas .
> > > *Cc:* discussion at sipforum.org
> > > *Subject:* Re: [SIPForum-discussion] very imp question about route&
> > > recordroute
> > >
> > >
> > >
> > > My understanding about this is:
> > >
> > >
> > >
> > > P1 is the proxy server in A's domain, so the address of P1 should be
> > > configured in the A's client.
> > >
> > > when P1 receive the request it will do the DNS query to find the
> > > location of the next hop in the target domain (as per the line mentioned by
> > > Srinivas) and then send the request to P2 which will inturn forward the
> > > request to B
> > >
> > >
> > >
> > >
> > >
> > > *Deepanshu Gautam**
> > > *R&D Engineer
> > > Huawei Technologies Co. Ltd.
> > > Nanjing Institute, No 91 BaiXia Rd.
> > > Nanjing, Jiangsu, P. R. China 210001
> > > Mobile: +86-13585147627
> > > Email: depanshu at huawei.com
> > >
> > >  ----- Original Message -----
> > >
> > > *From:* Srinivas . <nsrinivas at techmahindra.com>
> > >
> > > *To:* William Prusty <williamp at techmahindra.com> ; mwilliam prusty<callwilliam90653 at rediffmail.com>;
> > > discussion at sipforum.org
> > >
> > > *Sent:* Monday, April 23, 2007 6:44 PM
> > >
> > > *Subject:* Re: [SIPForum-discussion] very imp question about route &
> > > recordroute
> > >
> > >
> > >
> > > William Refer RFC 3261 Section.10.
> > >
> > >
> > >
> > > If a user wants to initiate a
> > >
> > > session with another user, SIP must discover the current host(s) at
> > >
> > > which the destination user is reachable. This discovery process is
> > >
> > > frequently accomplished by SIP network elements such as proxy servers
> > >
> > > and redirect servers which are responsible for receiving a request,
> > >
> > > determining where to send it based on knowledge of the location of
> > >
> > > the user, and then sending it there.
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >  ------------------------------
> > >
> > > *From:* William Prusty
> > > *Sent:* Monday, April 23, 2007 1:36 PM
> > > *To:* Srinivas .; mwilliam prusty; discussion at sipforum.org
> > > *Subject:* RE: [SIPForum-discussion] very imp question about route &
> > > recordroute
> > >
> > >
> > >
> > > Thank a lot srinivas. Plz make me clarify one thing more
> > >
> > >
> > >
> > >                 If A doesn't know IP address of p1 then how the invite
> > > request will reached at B
> > >
> > >
> > >  ------------------------------
> > >
> > > *From:* discussion-bounces at sipforum.org [mailto:
> > > discussion-bounces at sipforum.org] *On Behalf Of *Srinivas .
> > > *Sent:* Monday, April 23, 2007 11:05 AM
> > > *To:* mwilliam prusty; discussion at sipforum.org
> > > *Subject:* Re: [SIPForum-discussion] very imp question about route &
> > > recordroute
> > >
> > >
> > >
> > > William my comments inline
> > >
> > >
> > >  ------------------------------
> > >
> > > *From:* discussion-bounces at sipforum.org [mailto:
> > > discussion-bounces at sipforum.org] *On Behalf Of *mwilliam prusty
> > > *Sent:* Saturday, April 21, 2007 10:20 AM
> > > *To:* discussion at sipforum.org
> > > *Subject:* [SIPForum-discussion] very imp question about route &
> > > record route
> > >
> > >
> > >
> > >
> > > can any body tell that
> > >
> > > suppose the call setup is lke  A  p1    p2    B
> > >
> > > here A is user agent client. B is user agent  server. p1 & p2 are
> > > proxy.
> > > 1.let A has generated an  INVITE request to B . in which case the
> > > invite request generated by A will conatin ROUTE header field.????
> > > *[Srinivas]  Generally , proxy P1 gets IP address of B from location
> > > server also if there are any proxies in between. *
> > >
> > > *               Proxy P1 (generate INVITE) fills route and send
> > >  INVITE. *
> > >
> > > *User A can fill route set only if it knows the proxies between user A
> > > and user B. *
> > >
> > >
> > > 2. let p1 has rcved the INVITE request containg ROUTE heder field.
> > > is it mandatory that the invite from point p1 to p2 will conatin
> > > RECORD ROUTE heder field.????? if yes why if not why???
> > >
> > > *[Srinivas] In some cases, it may be useful for proxies in the SIP
> > > signaling path to see all the messages pass between the endpoints for the
> > > session. In that case it will add RECORD ROUTE.  If it don't want to be in
> > > the path, it will not add the RECORD ROUTE. *
> > >
> > >
> > > plz anser
> > >
> > >
> > >
> > > [image: diago sigline]<http://adworks.rediff.com/cgi-bin/AdWorks/click.cgi/www.rediff.com/signature-home.htm/1050715198@Middle5/1165423_1159521/1164587/1?PARTNER=3&OAS_QUERY=null%20target=new%20>
> > >
> > >
> > >
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