[nsp] GSR Queueing Question

[Dan Armstrong]

I am having a moral crisis about ATM queuing on the 12000 GSR, and wonder if
anybody has an opinion on this:

The ATM line cards on a GSR do not support per-VC queuing.  On a 7206, they do.

We have a Cat edge switch with customers in it, with an OC12 1483/LANE card that
trunks each VLAN (customer) back to an OC12 card on a GSR.  Each customer has a
separate subineferace on the router, and PVC that maps to a VLAN on the switch.

There are a mix of 10 meg and 100meg and 1000meg customers on that switch.  Back
in the day, we had a 7206 router in the GSRs place, with an ATM card, and it
_did_ support Per-VC queuing.  We would set each customer's PVC up on the router
at their subscribed rate to limit traffic coming from the router down to the
customer to that speed.  We would set each PVC up on the 1483/LANE card at the
same subscribed rate, to limit the traffic coming from the customer.  This
appeared to work very well.

Enter the GSR, no Per-VC queuing.  Does it still make sense for me to set each
customer's PVC up on the GSR at the subscribed rate (some 10, some 100, some
1000)?  Or should I just set them all up UBR, and let the switch & 1483/Lane card
handle dropping frames that exceed the speed of the customer's port?

Will there be any negative impact on performance if one customer gets whacked
with traffic, and overrun some buffer?

Thanks,
Dan.