[c-nsp] TCAM refresher

[TCIS List Acct]

Justin M. Streiner wrote:
> Someone I know is considering upgrading the core network device in their 
> data center to a 6500/Sup2/MSFC2.  They take three full BGP feeds from 
> their transit providers.  My initial caution to them about going with the 
> Sup2 instead of a Sup720/3BXL was that the Sup2 is limited to about 250k 
> TCAM entries assuming they're not running uRPF.  Given the size of a full 
> Internet routing table these days, that allows them a little bit of 
> headroom, but not much, plus this doesn't take into account their existing 
> access-lists, policies, local routes, multicast, Netflow, NAT, etc...
> That said, it would seem that a Sup2 would work for now, but it won't be 
> very long before it would need to be upgraded, i.e. they'd be better off 
> going with the 720/3BXL straight out of the gate.

We are in a similar situation -- considering a 6500/Sup2/MSFC2 for core.  Am I 
to understand that, if we take three full BGP feeds (lets say at 200K routes a 
piece, for a total of 600K routes), that the number of BGP routes does not 
translate 1:1 -- meaning that only 1 route will be chosen and used by the TCAM 
at a time, so as long as the number of total routes from any one BGP feed does 
not exceed ~240K, we will be OK?

--Mike