Subject: [SIP] Question on Contact, and Route in the draft.

From: Sunitha Kumar <[email-masked]>
Date: Mon, 24 Jul 2000 13:33:43 -0700

Quoting from pg:68 ,
If the request featured a Contact header field, the Contact header value
is appended to the Route header list.

Is this the initial request? If that is so, it cannot have the Route
header list.

If this is the next request from the same end point, then the Route
header list is
indeed present(assuming we have had proxies add Record-Route). however,
in this
case, it does not make sense to add the Contact to the Route list, (
since the Route list contains the route to get to the destination).

Could some one explain this.

thanks much.

--
Sunitha Kumar
http://www.vovida.com

---

From: Dvir Oren <[email-masked]>
Date: Tue, 25 Jul 2000 10:51:35 +0300 (IDT)

> If this is the next request from the same end point, then the Route

The problem only arrises on future requests.  On the first request,
each proxy will pass it on to the next proxy, until it reaches the
destination (adding Record-Route fields as necessary).  On the return
path (of the replies), the Via fields will be used.  Now, for sending
ACKs and BYEs, you will want to know to which proxies to send.  This
is done by changing Record-Route to Route.  The Contact field is
needed by the last proxy, to know to which destination it needs to
arrive to.

When the last proxy receives the ACK, the last Route field will be the 
value of the Contact field, which points to the desired destination.

-- 
Dvir Oren               <[email-masked]>
Lucid VON Ltd.     <http://www.lucidvon.com>
9 Saloniki St.,        Tel-Aviv       Israel
Tel:  +972 3 644 3038  Fax:  +972 3 644 3039

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---

From: Jonathan Rosenberg <[email-masked]>
Date: Wed, 26 Jul 2000 02:09:49 -0400

Sunitha Kumar wrote:
> 
> Quoting from pg:68 ,
> If the request featured a Contact header field, the Contact header
> value is appended to the Route header list.
> 

It does refer to the initial request. Yes, that initial request doesn't
contain the Route header. The Route list the text is referring to is the
Route list constructed by the UAS used in subsequent requests back to
the caller, not a Route list present in the received original request
(there is none).

-Jonathan R.

-- 
Jonathan D. Rosenberg                       72 Eagle Rock Ave.
Chief Scientist                             First Floor
dynamicsoft                                 East Hanover, NJ 07936
[email-masked]                     FAX:   (973) 952-5050
http://www.cs.columbia.edu/~jdrosen         PHONE: (732) 741-7244
http://www.dynamicsoft.com