[c-nsp] exceeding the hardware maximum routes in a 720BXL

[Lincoln Dale]

Gordon Bezzina wrote:
> Hi,
>
> Just a quick question what will happen if you exceed the maximum routes
> That the FIB TCAM can store.
>
> c7600#sh mls cef maximum-routes 
> FIB TCAM maximum routes :
> =======================
> Current :-
> -------
>  IPv4 + MPLS         - 512k (default)
>  IPv6 + IP Multicast - 256k (default)
>
>
> c7600#
>
>
> Will switch completely to software routing, or just switch the
> Excess routes to software routing? Or will it drop routes or worst
> Still crash!?
>   
it will switch to partial h/w, partial s/w.
a wildcard will be installed that matches on anything that doesn't fit 
into the table (i.e. it'll be a punt-to-software for "0/0").
>
> Also is there a best practice on changing the default maximum routes
> Allocations?
>   
default is 50/50 split between IPv4/MPLS / IPv6/Multicast.  its perhaps 
difficult to crystal-ball uptake of IPv6 over the next 2 years, but its 
probably fair to say the current defaults are ok.


cheers,

lincoln.