This question is in regards to the proper placement of a QoS policy for WAN interfaces.
I am running Frame Relay between our CE-PE connections where we interface with the provider for MPLS services. In doing this, we end up with a subinterface, and I'm curious about the application of the QoS policies... I've heard two schools of thought on this; one that feels you should always configure a map-class under the PVC and apply the QoS policy there, and the other that feels you can just apply the QoS policy under the physical interface. Since we only run a single PVC, we apply the QoS policy under the physical interface... I haven't seen any issues so far, and results are identical when doing side-by-side comparisons.
Creating a 'map-class', ensuring the values are set properly, plus enabling traffic-shaping ends up being a lot of work for no perceived value.
All of the devices are at least 2811 series, ranging up to 7206's at higher-speed sites, and the results have been the same across all of the platforms.
(Tests were done using various router models, interface types, and an Agilent N2X Traffic Generator.)