[j-nsp] QoS in L2VPN

[Stefan Fouant]

> -----Original Message-----
> From: juniper-nsp-bounces at puck.nether.net [mailto:juniper-nsp-
> bounces at puck.nether.net] On Behalf Of Ibariouen Khalid
> Sent: Tuesday, December 01, 2009 7:43 AM
> 
> Dear community
> Can someone send me a document which explains QoS in L2VPN.

You'll probably not find a single comprehensive guide to doing QoS in an
L2VPN environment.  Having said that, all you really need to understand is
the format of the frames/packets at various points in transit and apply the
QoS parameters accordingly.

Depending on the access circuit and what type of interface cards you're
using, you'll have various options for performing classification, queuing,
and scheduling on the PE, for example, if you're doing Ethernet L2VPNs, you
can fully classify based on the 802.1p priority bits and treat accordingly.
Here is where you'll rewrite the EXP bits in the MPLS header as you push the
packets into the LSP, so you can achieve Per-Hop Behavior (PHP) in
downstream nodes.

On your P routers, you'd be doing Behavior Aggregate (BA) classification
traffic based on the EXP bits, assuming you've marked them appropriately on
the ingress PE.

One other thing to point out, if you're doing IP internetworking style of
L2VPNs, i.e. Frame Relay on one side, and ATM on the other, you can fully
classify using the DSCP bits in the IP header on your ingress PE, since PEs
fully look up to the Layer 3 headers in this environment.

A good start would be the Class of Service configuration guide -
http://www.juniper.net/techpubs/en_US/junos10.0/information-products/topic-c
ollections/config-guide-cos/config-guide-cos.pdf

Stefan Fouant
www.shortestpathfirst.net
GPG Key ID: 0xB5E3803D