The MPLS WG Archive

["Iren, Sami" <Sami.Iren@marconi.com>]

Nabil:
The problem you are describing is a generic problem
with E-LSPs, not specific to CLASSTYPE (or DiffServ TE).
When an E-LSP is signalled, the signalled bandwidth
is associated collectively to the whole LSP, not
individual PSCs. Therefore, it is not possible
to do diffserv resource adjustments (e.g., queue bandwidth)
based on the signalled bandwidth.
The draft you are pointing out is a good first attempt
to solve some of these issues. However, IMHO, E-LSPs and
DiffServ TE concepts still require a lot of work.

Regards,
--Sami

> -----Original Message-----
> From: Nabil Seddigh [mailto:nseddigh@tropicnetworks.com]
> Sent: Wednesday, November 07, 2001 11:29 AM
> To: Iren, Sami
> Cc: 'Vishal M'; mpls@UU.NET
> Subject: Re: CLASSTYPE object
> 
> 
> Sami,
> 
> Currently, the CLASSTYPE object cannot really be used with 
> E-LSPs in the manner you describe. The CLASSTYPE object is only
> useful with L-LSPs.
> 
> In order to utilize the concept of bandwidth pools in E-LSP,
> one needs to be able to signal traffic parameters per class 
> or per-PSC. That capability is not present in the standards today.
> 
> The closest proposal to achieve what you describe is the following:
> http://www.ietf.org/internet-drafts/draft-ganti-mpls-diffserv-
elsp-00.txt

Best,
Nabil Seddigh

> 
> Your understanding that the CLASSTYPE is used to
> specify the bandwidth pool to be used for allocating
> resources during LSP Setup is correct. In this context,
> the service class which is signalled via EXP bits
> (in the case of E-LSPs) dictate the treatment given
> to the individual packets, and the CLASSTYPE, which
> is signalled per LSP, dictates where the bandwidth
> is coming from (used in CAC).
> 
> [....deleted....]
>
> Ideally, I would prefer to get rid of the CLASSTYPE
> concept and advertise available bandwidth per service class.