Subject: Re: WG Last call : Comment on COS service and TSPEC

From: Francois Le Faucheur <[email-masked]>
Date: Thu, 08 Mar 2001 13:36:39 +0100

David , George, Lou,

At 19:00 02/03/2001 -0500, David Charlap wrote:

<clip>

>------------
>
>The second problem involves the use of this draft in conjunction with
>the latest changes to RSVP-TE (version -08).  Version -08 eleimates the
>COS service type from the TSPEC and FLOWSPEC objects.
>
>The DS draft requires that COS-type objects be used in order to signal
>an L-LSP without bandwidth reservations.  With the current revisions of
>these two drafts, this type of LSP can not be signalled at all.  It
>effectively makes it impossible to use RSVP-TE to signal a best-effort
>LSP (either E-LSP or L-LSP)
>
>Either the COS-type TSpec must be put back in RSVP-TE, or the DS draft
>must be updated to provide a means for singalling a best-effort LSP.
>
>-------------
>
>A third problem involves the fact that the SENDER_TSPEC is now optional
>in a Path message.  This means that routers conforming to this spec will
>be generating messages that non-DS-capable routers will be forced to
>reject.  The RSVP-TE draft still states that SENDER_TSPEC is a mandatory
>object.
>
>There is no mention of whether a FLOWSPEC is optional in Resv messages. 
>If the COS C-Type is eliminated, then FLOWSPEC must become optional, if
>a best-effort LSP is possible, since presence of an IntServ FLOWSPEC
>will indicate a bandwidth reservation.
>
>This will create a similar incompatibility as with the absence of
>SENDER_TSPEC in Path messages.
>
>It seems to me that routers implementing this draft will be unable to
>interoperate with routers that do not implement it.  IMO, this is
>unacceptible.
>
>-- David
> 

Based on the clarifications from George and Lou, I propose the 
following resolution for David's two comments above:

	* generally, "diff-ext" will be updated to simply align to the RSVP-TE 
draft with respect to signaling LSPs without bandwidth reservation. 
"diff-ext" will refer to RSVP-TE for details of how Null-Service/TSSPEC
are used to signal LSP without bandwidth reservation.

	* section 5.6 will be updated to reflect use of "Null-service" 
instead of "COS service". 

	* section 5.6 can probably be shortened (because parts of it came about 
simply because of the confusion that stemmed from the "COS service" and 
its associated COS field. I believe some of that confusion naturally
goes away with the use of Null-Service).

	* TSPEC will be made mandatory (in line with RSVP-TE-08)

Any comments/issues with this resolution?

cheers

Francois

PS: David, thanks a lot for catching this.

---

From: Sandeep Sharma <[email-masked]>
Date: Thu, 8 Mar 2001 11:17:42 -0600

Francois,

Your suggested changes are good!

One comment: I think, in the context of E-LSP and L-LSP, there is a need to
clarify use of the RSVP DCLASS object (RFC 2996) as referenced in the NULL
service.

Thanks,

- Sandeep

Sandeep Sharma
  Iris Labs

> -----Original Message-----
> From: Francois Le Faucheur [mailto:[email-masked]]
> Sent: Thursday, March 08, 2001 6:37 AM
> To: David Charlap; [email-masked]; [email-masked]
> Cc: [email-masked]
> Subject: Re: WG Last call : Comment on COS service and TSPEC