Hi, I think the RIR staff working on the new policy draft understand the issue. I believe the new draft will reflect this by moving away from a fixed percentage to using the huitema/durand ratio which is meant to give a consistent view of space utilization when using variable levels of hierarchy. Joao Damas RIPE NCC At 17:27 +0100 14/8/01, Peter Willis wrote:
Colleagues,
I've just done some calculations that shows the maximum theoritical utilisation that can be achieved is 75% whilst maintaining the minimum size of routing table. That is if you take a large number of subnets, each subnet containing a random number of hosts, and assign to each subnet the nearest power of 2 larger than the number of hosts, the utilisation you get is 75%.
This is a 75% utilisation per level of network hierarchy.
So if we assume 3 levels of network hierarchy and each level doing perfect routing aggregation and perfect address allocation we will get an overall utilisation of 0.75^3 = 0.422 == 42% overall utilisation for the TLA.
I'd like to bet that if we have a network with enough hosts to justify 64 bits of address space it'll also be large enough to require more than 3 levels of network hierarchy. Any requirements to get high address space utilisation out of IPv6 can simply be demonstrated to lack scaling qualities.
Regards,
------------------------------------------------------------------------------- Peter Willis | E-mail: peter.j.willis@bt.com IP Technology Strategist | Phone: 01473 645178 Fax: 01473 644506 BTexact Technologies CTO | -------------------------------------------------------------------------------
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