"Tactical" /24 announcements

William Herrin bill at herrin.us
Mon Aug 9 18:33:10 UTC 2021


On Mon, Aug 9, 2021 at 10:31 AM Sabri Berisha <sabri at cluecentral.net> 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), and we end up with 16,777,216 - 1,266,696 = 15,510,520 potential /24 advertisements.

Howdy,

It's not that simple. For example, 224/4 is not a 'reserved' space but
it can't appear in the unicast BGP table either. That alone is a
million routes unaccounted for in your math.

Regards,
Bill Herrin


-- 
William Herrin
bill at herrin.us
https://bill.herrin.us/


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