QOS / Shaping on MPLS Network

chharris41 · ‎03-31-2008

I have a 100MB ethernet going from my CE router (data center) to MPLS network PE. Approx 40 remote sites connect via frame relay (some single T1 and some MFR bundles) into MPLS network to access data center and other remote sites. I have been told it would be wise to shape the traffic down as it goes from the 100MB link into the MPLS cloud as there is a speed "mismatch" since remote sites are anywhere from 1.5 to 7.5MB and the 100MB could overwhelm these links and cause packets to be dropped/policed in MPLS cloud. Would this be advisable? If so any pointers would be appreciated as to how to implement this. I suppose I'd have to use class-maps to match destination addresses of remote sites and use shaping??

Joseph W. Doherty · ‎03-31-2008

If you're permitting, or have, traffic site-to-site, i.e. other than pure hub-and-spoke, you can't easily control the MPLS egress congestion, other than within the MPLS provider's QoS model. This negates much of the benefit of shaping at your large bandwidth site.

If there is no competition for MPLS egress bandwidth, you can effectively deliver QoS via shaping at your hub, but if the MPLS provider offers an adequate QoS model, it's usually simpler to just use it, especially to maintain.

If you were going to do it, using one class-map per destination site with a shape command would work. You can optionally prioritize with a child policy.