[c-nsp] 2851 throughput / guidance

[Matthew Marlowe]

>> 
>> About 95% of the traffic through the devices will be HTTP and HTTPS,
>> probably in the 10mbps - 30mbps range.  The 2851s wouldn't be a really
>> long term solution, and once we start to hit the 70-90mbps range we
>> would be ready to replace them with something much bigger.
>> 

Are you really going to be able to get 70-90Mbps through
the 2851 w/ non-trivial acls + CBAC enabled?

We have a 3845 w/ CBAC/IPS/QoS enabled and I'd be happy
if it even supports 100Mbps.  The cisco performance docs say
we'll get somewhere between 45Mbps to 256Mbps performance
depending on what features are enabled on the 3845.
Currently we see about .8% cpu util per Mbps.

If I remember, the 3845 has about twice the cpu of the 2851.
I wouldn't plan on being able to get more than 50Mbps on a 2851
in a reasonable hosting provider configuration.

Regards,
Matt