In general, dialog initiating requests and target refresh (in-dialog) 
requests (and non-failure end-to-end responses) always carry the remote 
target. There is no special case for in-dialog requests. The rules for 
whether or not a Contact header is included do not depend on whether the 
request is "in-dialog" or not.

INVITE requests and 1xx/2xx (except 100 Trying) responses MUST have a 
Contact header whether its an initial INVITE or a re-INVITE (even if it is 
not changed). Other target refresh requests (UPDATE, SUBSCRIBE, and NOTIFY) 
also require a Contact header in the request and non-failure responses.

cheers,
(-:bob

Robert F. Penfield
Chief Software Architect
Acme Packet, Inc.
71 Third Avenue
Burlington, MA 01803
[EMAIL PROTECTED]

----- Original Message ----- 
From: "John Williams" <[EMAIL PROTECTED]>
To: "Frank Shearar" <[EMAIL PROTECTED]>
Cc: "SIP Implementors" <[email protected]>
Sent: Monday, February 26, 2007 6:51 AM
Subject: Re: [Sip-implementors] Target refresh requests


> Hello,
>
> I think you can put a contact in a re-INVITE, even if the IP address
> hasn't changed. It will make a sort of "touch" on the remote target.
>
> john
>
> Le lundi 26 février 2007 à 13:20 +0200, Frank Shearar a écrit :
>> I've been trying to wrap my head around in-dialog requests. It LOOKS like 
>> if
>> you make in-dialog requests you DON'T put in Contact headers, right?
>>
>> Unless you're doing a target refresh, that is, changing the Remote URI of
>> the
>> peer's dialog state. And the only way (in RFC 3261) is with an INVITE?
>>
>> Thus, if you send an in-dialog INVITE, it's a target refresh if and only 
>> if
>> it has a Contact header?
>>
>> Does that mean that if you haven't changed your IP (or similar) you 
>> SHOULD
>> NOT
>> put a Contact in the INVITE/target refresh request?
>>
>> frank
>>
>> _______________________________________________
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>
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