"Tactical" /24 announcements

Tue Aug 10 09:29:06 UTC 2021

Sabri Berisha wrote:

> Just for fun, I did the math. A total of 16,777,216 /24s fit in 32
> bits. Take away all the reserved space as per IANA (this is 1,266,696
> /24s, see below),

 > 240.0.0.0/4	1048576

I think we should also take away multicast addresses of

 > 224.0.0.0/4	1048576

because multicast route can not be aggregated and must
be treated as /32.

Anyway,

> The largest FIB table I have seen (hi Jim!) was 3,563,546 routes in
> hardware. This was in a lab environment, of course.

for /24, these days, having 16M entry SRAM (simple one, not
TCAM) is trivially easy.

							Masataka Ohta