* Wolfgang Tremmel > > No. But renumbering an IX is *pain*. A lot of pain. You want to > > avoid that if possible. > > A /26 allows (given that the IX uses about 2-4 IPs itself) about 60 > > customers. > > > > So according to the numbers, for 70% of the IXes this will never > > fill up, so no need for renumbering. > > Depending on how quickly it filled up, you then go either for a /25 > > or a /24. > > > > To sum up: > > - if you start with a /26 ==> 30% has to renumber > > - if you start with a /29 ==> 75% has to renumber ---> more pain!
I do not think that insulating IX-es from possibly having to renumber when they double in size should be something this policy should aim to accomplish. (If it was, we could simply give everyone /22s or larger.) IPv4 is a limited and finite resource – the goal should be to make it last. Looking at Matthias's graphs, for each new IX that is assigned a /26, there is an about 70% chance of that assignment being wastefully large. Making such assignments will inevitably result in other new IX-es being denied assignments, because there is nothing left, because the space those IX-es *could* have used was given to first IX – even though the first IX had no need for it. So, all in all, I think that assigning IX-es the amount of space they *actually* need, but no more, and require them to renumber into a larger prefix whenever they double in size is a fair deal, when balanced against avoiding waste and preserving space for future IX-es (and existing growing IX-es for that matter). * David Farmer > I think maybe we want something in between; what do /27 and /28 look > like? > > /29 could be forcing too much pain into the system, and /26 > probably isn't enough pain in the system. > > Furthermore, /29 seems a little too small for a reasonable growth > cycle before having to renumber. 50% fill of a /29 would be 3 of 6 > usable addresses. Meaning many IXes could almost immediately qualify > for a larger subnet, and they would have very much time to implement > a renumbering process. The policy states that you get what you need to have a 50% utilisation one year from assignment. Thus, in order to get an initial /28 assignment and skip over a default /29, the IX would need to have a realistic plan to have eight members within a year of the founding of the IX (or possibly just six, if the NCC considers the network and broadcast addresses as «utilised»). That is a *very* low bar to clear. But if IX cannot clear that low bar, I'd say they should not start out with a /28 (or larger) either. https://www.ripe.net/publications/docs/ripe-733#61 > Basically, a /29 is probably too small to be practical. > Well, according to Mathias's report, 25% of all IX-es would manage just fine with a /29… By the way, last I checked there were a number of unassigned fragments smaller than /24 rotting away in the NCC's inventory, due to there being no policy that allowed for their assignment. IX-es are one of the very few places where those can be used, so they could be all added to the reserved IXP pool and actually do some good there. Tore -- To unsubscribe from this mailing list, get a password reminder, or change your subscription options, please visit: https://lists.ripe.net/mailman/listinfo/address-policy-wg
