[c-nsp] What QoS methods are available on ATM IMA lines?

[Anton Kapela]

> policy-map LIMIT_BULK_OUT
>   class PRIO
>     police 2048000 256000 256000 conform-action transmit  
> exceed-action transmit  violate-action transmit
>   class BULK_OFFICE_HOURS
>     police 2048000 256000 256000 conform-action transmit  
> exceed-action transmit  violate-action drop
>   class class-default
>    fair-queue
>    random-detect

Imho, this is sort of 'inverted' way to get space for your priority
data.  Do something like:

Class prio
 priority 400 (400kbits of priority queue)
Class not-prio
 bandwidth $blah
Class bulk
 bandwidth $less_than_blah

Also, you have to set something other than UBR on the PVC. That is, set
ABR or CBR 'bitrates' to tell the SAR what the real playout rate is,
otherwise congestion won't form at the right places, and backpressure
won't cause priority queuing to kick in. 

For extra points, set the wic/pa/etc level tx-ring to 1 or 2 packets, as
this will quicken the rate at prioritization can occur in response to
congestion underway.

-Tk