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Cell Relay Retreat>MPLS WG Archive>month:2002-Oct> msg00118



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DiffServ MPLS over Ethernet (L-LSP vs E-LSP)

  • From: Curtis Villamizar <curtis@workhorse.fictitious.org>
  • Date: Mon, 21 Oct 2002 13:37:10 -0400
  • cc: "'curtis@fictitious.org'" <curtis@fictitious.org>, "'Vishal M'" <vishal_study@yahoo.com>, mpls@UU.NET, Shahram Davari <Shahram_Davari@pmc-sierra.com>


In message <AF5018AC03D1D411ABB70002A509132678E63C@TLV1>, Sasha Vainshtein writ
es:
> Curtis and all,
> Can you provide any suggestions/pointers as to how DiffServ and 
> 802.1q markings should be mapped? 
> Because, IMHO, just having 802.1q is not enough, you should decide
> how to use it.

I'm not a big fan of 802.1q.

Mapping EXP into 802.1q signaling is straightforward.  This mapping is
sufficient for unsignaled E-LSP.

The mapping of 802.1q priorities to packet treatment is not
straightforward.  I'd argue that what most switches are capable of
doing with 802.1q priorities does not support diffserv, particularly
AF, L-LSPs, or signaled E-LSPs.  For AF service, the EXP bits must be
modified even for unsignaled E-LSPs so any switch relying solely on
802.1q signaling is inherently broken wrt AF service.

> With best regards,
>                                    Sasha Vainshtein

I haven't kept up with what ethernet switches are doing in this
regard.  Shahram may be better able to answer this.

Curtis