[nsp] rate-limiting

[Raymond, Steven]

> Hi Christopher,
> 
> I know that when using traditional CAR, your policer 
> bucketsize values 
> are incorrect.  I assume the policer is implemented similarly 
> with the 
> modular QoS on the same platforms.

Can anyone point to a CCO link that usefully describes the meaning and use
of the bucketsize parameters?  In my trial & error testing with a smartbits,
I found that the closest approximation to limit a FE circuit to say, 50Mb/s,
would be something like this:

interface fe0/0/0
rate-limit input 50000000 12500000 12500000 conform-action transmit
exceed-action drop
rate-limit output 50000000 12500000 12500000 conform-action transmit
exceed-action drop

Where the 12500000s are the actual signalling rate of the media in terms of
bytes/second.  With much smaller numbers, smartbits showed that achieved
throughput was much lower than 50,000,000 bits/second at layer 2 (similar to
the original poster's results).  These numbers usually let a little more
than 50,000,000 bits/sec at layer 2 through, but I'd rather be over than
under.

Furthermore, is there a difference in the configuration when doing straight
interface rate limiting (CAR?) vs the modular QOS style?

Thanks