Re: 90 IPv6 sub-TLA allocations made
Hiya all, In my view it is not so ambitious to be recommending /16 allocations to "supernational" organisations as this is the policy originally recommended in RFC2374 and elsewhere. On the other hand: "Will these supernational organisations be advertising parts of this /16 into the global routing table". If the answer is yes, then I think they should be making multiple regional or national requests, and receiving multiple /20 or /24 allocations according to their likely longterm requirements in each region. Everytime an LIR requests and gets additional addresses because of an insufficiently small original allocation (whether through the 80% rule, or 90% according to RFC2450 !! or my suggested 10% rule), the RIR's have effectively made a mistake as this means one unnecessary route in the routing table. I'm not suggesting the RIR's give a /16 (or /20,/24,/28,/32, for that matter) to anybody who asks. The requester must justify that such an allocation is appropriate (with the RIR's taking a much more generous stance in contrast to what they need to do with IPv4). Cheers Dave BT Ignite GmbH, On Sun, 12 Aug 2001, Tim Chown wrote: ->As a group, we have not discussed more ambitious suggestions such as those ->at http://www.djp.net/ipv6/proposal.html where a /16 is suggested for the ->"supernational" organisations. ->Tim
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 | -------------------------------------------------------------------------------
This is not including the needed aggregation for multi-national registries, its fine for a single network but, still would tie your hands when sub-allocating to multiple LIR's. Regards Stephen Burley UUNET EMEA Hostmaster
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 | --------------------------------------------------------------------------
This is not including the needed aggregation for multi-national registries, its fine for a single network but, still would tie your hands when sub-allocating to multiple LIR's.
This is simply accomodated by mutliplying the maximum utilisation figure by 0.75 for every layer of hierarchy or aggregation in the network. So for a 3 layer network plus another layer for international aggregation the maximum utilisation falls to 0.75^4=0.316 == 32%. This is the theoritical maximum address utilisation that can be achieved without breaking aggregates. I think we should penalize anyone who gets a better address utilisation than this because they are obviously announcing more routes than they need to ;-) Peter.
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 | -------------------------------------------------------------------------------
--
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
Will the new draft include the priciple of MIR's which i detailed on the list (which stangly got no negative response) and will it also understand the concept of sub-allocation? Regards, Stephen Burley UUNET EMEA Hostmaster ----- Original Message ----- From: "Joao Luis Silva Damas" <joao@ripe.net> To: "Peter Willis" <pjw@ip-engineering.bt.com>; "Dave Pratt" <djp-ripe-lists@djp.net> Cc: "lir-wg" <lir-wg@ripe.net>; "ipv6-wg" <ipv6-wg@ripe.net> Sent: Wednesday, August 15, 2001 3:03 PM Subject: Re: 90 IPv6 sub-TLA allocations made 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 |
---------------------------------------------------------------------------
--
At 15:39 +0100 15/8/01, Stephen Burley wrote:
Will the new draft include the priciple of MIR's which i detailed on the list (which stangly got no negative response) and will it also understand the concept of sub-allocation?
I can't answer this directly as I haven't seen the latest version, but Mirjam's keyboard is on fire from all the typing going on, so I think the new draft is coming real soon now. Joao
Regards, Stephen Burley UUNET EMEA Hostmaster
--
Hi, On Wed, Aug 15, 2001 at 03:39:56PM +0100, Stephen Burley wrote:
Will the new draft include the priciple of MIR's which i detailed on the list (which stangly got no negative response) and will it also understand the concept of sub-allocation?
Without knowing anything about that draft :-) I can only speculate. On the concept of MIRs - I don't think they are necessary. This is something that a LIR should do internally - and this means the concept of sub-allocation should be legalized (and formalized) now. LIRs already do sub-allocations, because it's necessary. The hostmasters know this, but frown on it, because it's not in the official policies. So let's change 'em (at least for IPv6, where aggregation is MUCH more important than conservation). Gert Doering -- NetMaster -- SpaceNet AG Mail: netmaster@Space.Net Joseph-Dollinger-Bogen 14 Tel : +49-89-32356-0 80807 Muenchen Fax : +49-89-32356-299
participants (5)
-
Dave Pratt -
Gert Doering -
Joao Luis Silva Damas -
Peter Willis -
Stephen Burley