The MPLS WG Archive

[Curtis Villamizar <curtis@workhorse.fictitious.org>]

In message <4B6D09F3B826D411A67300D0B706EFDEB039FE@nt-exch-yow.pmc-sierra.bc.ca
>, Shahram Davari writes:
> Diffserv is not supported for non-802.1q networks.
> 
> -Shahram


Shahram,

Diffserv works perfectly fine on non-802.1q point to point links
(which is quite common in ISP POPs).  It also happens to work if you
are using GbE or 10GbE in a aggregation or access application where
the circuits feeding in are lower speed.  This only works because the
sum of all feeds is significantly less than the GbE/10GbE bandwidth.

This is just a minor clarification and generally your statement
"Diffserv is not supported for non-802.1q networks" is true.  Point to
point ethernet links and constrained feed bandwidth in ISP aggregation
or access POPs can be considered special cases.

The point is that some ISPs are using GbE/10GbE with diffserv and
without 802.1q, though admitedly in special situations.

Curtis


> > -----Original Message-----
> > From: Vishal M [mailto:vishal_study@yahoo.com]
> > Sent: Friday, October 18, 2002 10:03 PM
> > To: mpls@UU.NET
> > Subject: DiffServ MPLS over Ethernet (L-LSP vs E-LSP)
> > 
> > 
> > 
> > Hi,
> > 
> > If someone wants to use MPLS over ethernet and support
> > DiffServ extensions for MPLS (i.e MPLS DS TE), can one
> > still choose between using E-LSP or L-LSPs ? 
> > 
> > The reason for the doubt is:
> > The Ethernet header (like ATM) doesn't have any QoS
> > information field (unless 802.1q is supported). So
> > does that imply that E-LSP can't be used when ethernet
> > is the underlying media (and 802.1q is not supported).
> > 
> > Is L-LSP the only choice then?
> > 
> > Thanks for your inputs,
> > 
> > Regards,
> > Vishal.
> > 
> > 
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