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Re: 90 IPv6 sub-TLA allocations made, ipv6-wg ipv6-wg@localhost

  • To: Peter Willis < >
    Dave Pratt < >
  • From: Joao Luis Silva Damas < >
  • Date: Wed, 15 Aug 2001 16:03:50 +0200
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,


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Peter Willis		            | E-mail: peter.j.willis@localhost
IP Technology Strategist            | Phone:  01473 645178 Fax: 01473 644506
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