Rate-limiting BCOP?

[bryan at shout.net (Bryan Holloway)]

I'm curious if the community would be willing to share their 
best-practices and/or recommendations and thoughts on how they handle 
situations where a customer buys X amount of bandwidth, but the physical 
link is capable of Y, where Y > X. (Yes, I speak of policy-maps, 
tx/rx-queues, etc.)

For example, it might be arguably common to aggregate customer links 
Layer 2, and then push them upstream to where they anchor Layer 3. That 
Layer 2 <-> Layer 3 could be a couple of meters or several kilometers.

So, as I see it, my options are:

* Rate-limit at the Layer 2 switch for both customer ingress/egress,

* Rate-limit at the Layer 3 router upstream, i/e, or

* Some combination thereof? E.g.: Rate-limit my traffic towards the 
customer closer to the core, and rate-limit ingress closer to the edge?

I've done all three on some level in my travels, but in the past it's 
also been oftentimes vendor-centric which hindered a scalable or 
"templateable" solution. (Some things police in only one direction, or 
only well in one direction, etc.)

In case someone is interested in a tangible example, imagine an Arista 
switch and an ASR9k router. :)

Thoughts?