Re: [Sip] RFC 3608 on Session Initiation Protocol (SIP) Extension Header Field for Service Route Discovery During Registration

[Jonathan Rosenberg <[e-mail]>]

You can't really add support for a Supported mechanism later, since 
you run into the problem that if Suported is missing from the 
REGISTER, you can't know if thats because service route isn't 
supported, or if it is supported but the new "add Supported to service 
route draft" is not supported.

The reason why Supported makes sense is, without it, the registrar has 
no way to know whether or not the UA will be able to process the 
Service-Route header field in the response. As such, it will end up 
always needing to insert it, even if none of the UAs understand it. 
THat is wasteful.

-Jonathan R.

Bernie Hoeneisen wrote:

> Hi Chris,
> 
> Let me make a brief excursion to the history of Service-Route: I remember
> some discussions concerning the possible usage of an option-tag for
> (P-)Service-Route in the early stage of the I/D. At that time the working
> assumption was, that this would be a P-header field
> (i.e. P-Service-Route). Since you cannot Require a P-header field, the
> discussion immediately ended at that time.
> 
> Lateron working assumption was changed: the P-header field was changed to
> a normal header field. But nobody has brought up again a requirement
> for an option-tag service-route.
> 
> In case such a requirement turns out be useful, we could consider to make
> an additional document describing the Require/Supported behavior with
> Service-Route.
> 
> What is your main motivation for such an option-tag for service-route?
> 
> cheers,
>  Bernie
> 
> 
> On Thu, 9 Oct 2003, Chris Boulton wrote:
> 
> 
>>Dean, Bernie,
>>
>>This may seem a silly question (I'm sure I will be told that it is ;-),
>>BUT I was wondering why the use of the 'Supported/Require' headers are
>>not required with this extension.
>>
>>Regards,
>>
>>Chris.
>>
>>
>>
>>>-----Original Message-----
>>>From: [e-mail] [mailto:[e-mail]]
>>>Sent: 09 October 2003 01:01
>>>Cc: [e-mail]; [e-mail]
>>>Subject: [Sip] RFC 3608 on Session Initiation Protocol (SIP) Extension
>>>Header Field for Service Route Discovery During Registration
>>>
>>>
>>>A new Request for Comments is now available in online RFC libraries.
>>>
>>>
>>>       RFC 3608
>>>
>>>       Title:      Session Initiation Protocol (SIP) Extension Header
>>>                   Field for Service Route Discovery During
>>>                   Registration
>>>       Author(s):  D. Willis, B. Hoeneisen
>>>       Status:     Standards Track
>>>       Date:       October 2003
>>>       Mailbox:    [e-mail], [e-mail]
>>>       Pages:      17
>>>       Characters: 35628
>>>       Updates/Obsoletes/SeeAlso:    None
>>>
>>>       I-D Tag:    draft-ietf-sip-scvrtdisco-04.txt
>>>
>>>       URL:        ftp://ftp.rfc-editor.org/in-notes/rfc3608.txt
>>>
>>
>>
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>>
> 
> 
> _______________________________________________
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> This list is for NEW development of the core SIP Protocol
> Use [e-mail] for questions on current sip
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> 

-- 
Jonathan D. Rosenberg, Ph.D.                600 Lanidex Plaza
Chief Technology Officer                    Parsippany, NJ 07054-2711
dynamicsoft
[e-mail]                     FAX:   [phone]
http://www.jdrosen.net                      PHONE: [phone]
http://www.dynamicsoft.com


_______________________________________________
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This list is for NEW development of the core SIP Protocol
Use [e-mail] for questions on current sip
Use [e-mail] for new developments on the application of sip