[c-nsp] TCAM refresher

[Florian Weimer]

* Brian Turnbow:

> The fib is used to populate the tcam.  So yes all 600K routes will
> not go in , but besides bgp all your local routes will.

And your ARP table entries.  Of course, Cisco could fix that by
aggregating entries before they end up in the TCAM: If both
192.0.2.8/30 and 192.0.2.12/30 have the same adjacency, you can do
with a route for 192.0.2.8/29 instead.  But there are probably reasons
for not doing it this way in the first place, so it's unlikely that
such a change will arrive in time.