Aris Lambrianidis wrote on 04/06/2019 18:03:
Consulting the PCH IXP directory as Nick did earlier (as well as the Euro-IX one), I think it is also reasonable to say that allocating a /24 is ambitious for the overwhelming majority of cases.
Only 64 of listed IXPs have equal to, or more than, 100 participants, out of 958 IXPs, or about 6.6%.
In this light, perhaps the default allocation discussed in 6.1.4 should go down to a /25.
/25 is too small, even for smaller IXPs. ~400-500 of the entries in the PCH IXP directory are defunct. For the remainder, the participant numbers are inaccurate, mostly on the low side. A figure of about 500 active IXPs is largely corroborated by the IXP DB (650 entries, with some effectively defunct). The figure you need to look at is 50% usage rather than 100% usage. If you pin the assignment size to /25, then 50% of /25 is 64 participants, i.e. about ~20-25% of IXPs, not 6.6%. The current run-out rate for the RIPE pool is about 15k addresses per day. This means that a /16 is 4 days worth of allocations at the current rate. A /16 pool gives adequate breathing room for core internet infrastructure, with a /24 assignment size. The central question of this policy update is not the assignment size for IXPs, but whether it's worth investing 4 days out of 30 years worth of allocations in order to provide important flexibility for the internet core in the future. I'm inclined to think it is. Nick