Subject: MPLS support of diffserv

From: "Huang, Thomas" <[email-masked]>
Date: Fri, 22 Sep 2000 10:01:19 -0700

Hello Francois:

I have read through your draft on the MPLS support of diffserv.

I have the following questions:

1. any MPLS vendors have implemented the diffserv support per this draft?
and if so, what type of interoperability issues are out there?

2. to support diffserv in a mpls domain, the draft calls for extension of
RSVP-TE by adding a diffserv object to pass the PHB mapping info.
I have read some other proposals on extending RSVP for DiffServ
specifically. Do you see a need to converge them? or are there any efforts
in that area. What's your view on your draft for being a standard? or are
you making additional changes and WG has input too?

3. it seems to me we are mixing diffserv and mpls. My question is: is it
better off we do an INTERWORKING at MPLS ingress and egress? While inside
MPLS, established LSP/tunnel provides the equivalence to PHB..
I guess what I am trying to say is that we don't do PHB insider MPLS..

Help and Comments? 

Regards,
/Thomas

---

From: "Huang, Thomas" <[email-masked]>
Date: Fri, 22 Sep 2000 17:55:37 -0700

Hello Shahram:
Thanks for your comments. I have two quick followups.
You wrote: 
	MPLS has no QoS capabilities. In order to provide QoS you need to
use either
	Diffserv or Intserv or a similar technique.

I am not sure I agree with your first part of it. 

As far as I could see,
1. but RSVP-Te does have the ability to signal the QOS to the nodes along
the LSP. And MPLS network LERs and LSRs perform tunnel setup with QoS based
TE. 
2. current RSVP-TE (or LDP) has the ability to signal some level Intersev
QoS, CoS,policy ctype...
I can see the need for doing the BA or MF in PHB for non-signaled traffic
flows via MPLS network. But for signaled tunnels, could we just do an
interworking at edge LSRs? 

Well, if we have to deal with non-signaled DS i.e. the MPLS domain becomes a
DS domain, I agree we have to do BA or MF at each node.

Thanks.
/Thomas
-----Original Message-----
From: Shahram Davari [mailto:[email-masked]]
Sent: Friday, September 22, 2000 10:29 AM
To: 'Huang, Thomas'; Francois Le Faucheur
Cc: [email-masked]'
Subject: RE: MPLS support of diffserv 

Hi,

Please see my comments  in line:

> -----Original Message-----
> From: Huang, Thomas [mailto:[email-masked]]
> Sent: Friday, September 22, 2000 1:01 PM
> To: Francois Le Faucheur
> Cc: [email-masked]'
> Subject: MPLS support of diffserv 
> 
> 
> Hello Francois:
> 

I haven't seen any other proposal for extending RSVP-TE for Diffserv.
Therefore there is no effort in converging them. The WG has been working
on this draft for more than a year and we have included all the inputs.
This draft has passed the MPLS WG last call and is currently sent to IESG
to be published as a Proposed Standard. As far as I know IETF will not 
make any significant changes to a proposed standard unless there is a
serious
issue raised or the interoperability results show problems.

> I guess what I am trying to say is that we don't do PHB insider MPLS..

MPLS has no QoS capabilities. In order to provide QoS you need to use either
Diffserv or Intserv or a similar technique. Therefore if you have a network
that does not implement Diffserv or Intserv, that network would treat the
packets as BE, no matter if MPLS is present or not. And the interworking 
solution that you raised will map Diffserv packets to BE.

Regards,
-Shahram