[c-nsp] Catalyst TCAM Question

[Jon Lewis]

They should be software switched.  If you're moving much traffic through 
the box, that's not good.  You might want to filter the BGP feeds so 
you're carrying less than the max supported number of routes...though even 
if you filtered on RIR minimums, I'm not sure you'd still be able to fit 
the resulting number of routes into your 196k limit.  I know you could 
several years ago (i.e. 2007), but the global table was >100k routes 
smaller then.

On Thu, 5 May 2011, Bill Blackford wrote:

> Platform: 7600/SUP720-B
>
> If a box that can only handle sub 200k IPV4 routes in TCAM receives
> two full feeds and as shown below is only 'using' 196305 of them, is
> the delta of that 350k dropped or is it then processed in software?
> Looking a 'sh route sum' it looks like a full table in the FIB. 'sh fm
> sum' shows nothing INACTIVE.
>
> <snip>
> L3 Forwarding Resources
>             FIB TCAM usage:                     Total        Used       %Used
>                  72 bits (IPv4, MPLS, EoM)     196608      196305        100%
>                 144 bits (IP mcast, IPv6)       32768           5          1%
>
>                     detail:      Protocol                    Used       %Used
>                                  IPv4                      196305        100%
>                                  MPLS                           0          0%
>                                  EoM                            0          0%
>
>                                  IPv6                           2          1%
>                                  IPv4 mcast                     3          1%
>                                  IPv6 mcast                     0          0%
>
>            Adjacency usage:                     Total        Used       %Used
>                                               1048576         199          1%
> </snip>
>
> I see this in the logs which was my first clue for asking this question:
>
> <snip>
> %MLSCEF-SP-7-FIB_EXCEPTION: FIB TCAM exception, Some entries will be
> software switched
> </snip>
>
> thank you in advance for any input.
>
> -b
>
>
>
> -- 
> Bill Blackford
> Network Engineer
>
> Logged into reality and abusing my sudo privileges.....
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  Jon Lewis, MCP :)           |  I route
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