[c-nsp] Cat 6500 - uRPF - FIB TCAM

[Blake Dunlap]

I strongly think you should read up on how CEF/dCEF work on the 6500, as
you seem to show a basic misunderstanding here.

Short version: There is 1 TCAM table with some caveats about how dCEF works
per card / spa.

-Blake

On Tue, Aug 14, 2012 at 6:50 PM, Brandon Applegate <brandon at burn.net> wrote:

> Hello,
>
> I know this has been mentioned over the years here and there, but I don't
> know that I fully understand the exact behavior.  I've always read 'urpf
> halves your tcam...'.  So this only applies to the interface on which it's
> configured, correct ?  So for example, in a single switch with the full
> routing table (using ipv4 for examples, and using simple even numbers not
> counting any built-in entries):
>
> uplink 1 - 400k routes
> uplink 2 - 400k routes
>
> customer interface 1 - 2 routes
> customer interface 2 - 2 routes
>
> So this is 400,004 entries.  Adding (strict) urpf to the customer
> interfaces (not the uplinks) would make this 400,008 ?
>
> I guess I'm just unsure of if urpf is added to a single interface (even a
> customer interface with 1 or 2 prefixes) - does this have some 'global'
> effect ?
>
> Thanks in advance.
>
> --
> Brandon Applegate - CCIE 10273
> PGP Key fingerprint:
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>
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