The MPLS-OPS Archive

["Hemant P. Kelkar" <hemant@cyberspace.org>]

Hi Rick,

#1.That means that for every DiffServ class there will be a separate FEC.
Well, that would  have been done at the ingress (LER) itself. But, once
the MPLS traffic reaches at the internetworking equipment, it seems as if
we have to remap FECs to DiffServ and allot a different label(here VPI/VCI
combination) for various flows. Is my interpretation correct ?

#2.Is the Drop precedence, you are indicating to, connected with the
ATM-CLP ?

#3.Can you give me all the AFxy classifications and brief idea what
1,2,3,4 stands for there ? I mean all x and y values ?

#4.Which draft/rfc should I refer to, for dealing with MPLS DiffServ<->ATM
QoS issues ?

Regards,
Hemant


Date: Wed, 19 Sep 2001 10:18:03 EDT
From: RickGall1@aol.com
To: hemant@cyberspace.org
Subject: Re: TE parameter mapping for heterogeneous networks.

Hope this helps some

I answered your sample and also provided an another sample

Your Sample

 User_A -->(((MPLS Cloud)))?(((ATM Cloud)))--->User_B.

 1) the ? can be a direct connection MPLS to a VPI/VCP. Just map the label
to
a VPI/VCP

 2) MPLS to DifServ to ATM
The best thing is not to use the exe pits for DifServ but relate DifServ
to a
FEC -- because not everyone used the Exe bits and they do not map well.

DifServ has 12 classifications AF11 to AF44  {(AFxy) where the x is the
class
and the y is the drop precedence} The Exe pits only give combinations for
7
groups so the best thing is to map to a label related to an FEC.


Sample 2

User A and B are IP and on IP networks they go from 802.1Q where they are
mapped to DifServ at the router or L3 switch. At the LER they are mapped
to
MPLS labels and FECs, at the MPLS cloud maps to ATM with Labels and ATM
maps
back to DifServ at the LER and back to DifServ and to 802.1Q

 User_A -->802.1Q/p ---> Difserv --->(((MPLS Cloud)))--- >(((ATM
Cloud)))--->

difserv ------->  802.1Q/p ------> User_B.


Hope this helps

Rick Gallaher
MPLS instructor


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