maximum ipv4 bgp prefix length of /24 ?

Thu Oct 5 22:51:09 UTC 2023

> On 6 Oct 2023, at 6:13 am, Owen DeLong <owen at delong.com> wrote:
> 
> Ratio of FIB to RIB is only part of the equation.
> 
> IPv6 is NOT under the disaggregation pressure that IPv4 is under because there is no pressure (other than perhaps scarcity mentality from those that don’t properly understand IPv6) to dense-pack IPv6 assignments or undersize IPv6 allocations.
> 
> Look at the difference in prefixes per ASN across the two tables and that tells a much grimmer story for IPv4 in terms of RIB growth vs. IPv6.

hmm - IPv4 is at [1], IPv6 is at [2]

Now I’m trying to understand what your grimmer story for IPv4 might be here Owen. Since 2005 the number of IPv4 FIB entries per origin AS has increased fropm 8 to 12 in the past 20 years - or a 50% increase. Over ther same period the number of IPv6  prefix advertisements per origin AS has increased from 1.5 to 6, or a fourfold increase. If anything, the IPv6 story appears to me to be a far greater cause for concern, but you may have a different interpretation of this data.

Geoff

[1] https://bgp.potaroo.net/cgi-bin/plota?file=%2fvar%2fdata%2fbgp%2fas2%2e0%2fbgp%2dentries%2das%2etxt&descr=Average%20entries%20per%20origin%20AS&ylabel=Average%20entries%20per%20origin%20AS&with=step@%82%966%88U

[2] https://bgp.potaroo.net/cgi-bin/plota?file=%2fvar%2fdata%2fbgp%2fv6%2fas2%2e0%2fbgp%2dentries%2das%2etxt&descr=Average%20entries%20per%20origin%20AS&ylabel=Average%20entries%20per%20origin%20AS&with=step