any dangers of filtering every /24 on full internet table to preserve FIB space ?

Edvinas Kairys at
Mon Oct 10 14:58:45 UTC 2022


We're considering to buy some Cisco boxes - NCS-55A1-24H. That box has
24x100G, but only 2.2mln route (FIB) memory entries. In a near future it
will be not enough - so we're thinking to deny all /24s to save the memory.
What do you think about that approach - I know it could provide some
misbehavior. But theoretically every filtered /24 could be routed via
smaller prefix /23 /22 /21 or etc. But of course it could be a situation
when denied /24 will not be covered by any smaller prefix.

What do you think about this approach ?

Also maybe you know - some advices for edge routers that have at least
8x100G interfaces and "good" memory for prefix count ? Thanks
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <>

More information about the NANOG mailing list