[c-nsp] Dynamic TCAM allocation/optimization? (was Re: N7K tcam handling)

[David Hughes]

On 12/03/2010, at 5:23 AM, Chris Woodfield wrote:

> And while we're on the subject, are there any reasons why Cisco (or any other vendor AFAIK) has seriously looked into methods of "optimizing" the TCAM? I'm thinking in terms of "If 10.0.0.0/16 and 10.0.1.0/24 both have the same next hop, why do you need two TCAM slots?"

So, as an example, in your RIB you have an entry for 10.0.0.0/16 and about 1,000 entries for more specific routes in net 10.  The supernet is withdrawn by a peer device and the router is left trying to work out which of the more specific FIB entries it yanked it needs to put back in (and if they'll even fit).  Sounds like a mine field.

I'd rather know if the table I receive will fit in FIB to start with and be done with it.  If my box is too small then I'm sure I can come up with a route-map that'll fix that in a predictable manner.


David
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