[c-nsp] service-policy on virtual interface

[Pete Templin]

Tony wrote:

>> From the card above you can see that unclassified traffic (COS 0)
>> will start getting discarded at 40% and as the queue gets fuller it
>> will progressively discard more. If the queue gets to 70% then ALL
>> COS0 traffic will be discarded. In queue 1 this 30% at the top of
>> the queue is for COS 2 & 3 packets in threshold 2.
> 
> This theoretically means that the maximum throughput you would see on
> the above card with just enabling QOS and not configuring anything is
> around 700Mbps (70% of 1Gbps). in reality it would probably be a bit
> less, but that would be absolute maximum

Can you clarify this for me?  If 999Mbps of traffic is arriving on an 
'ingress' port and is the only traffic leaving on an 'egress' port, 
there shouldn't be much if any queueing, right?  Queueing should only be 
occurring when the (instantaneous) packet arrival rate exceeds the rate 
at which the device can dispatch the packets, and as those queues get to 
various thresholds of %-full, they'll execute WRR to manage the queue 
depth, correct?

pt