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Re: v6 & DSL / Cable modems [was: Private use of non-RFC1918 IP space (IPv6-MW)]


From: Matthew Moyle-Croft <mmc () internode com au>
Date: Fri, 6 Feb 2009 21:12:54 +1030

My comment was regarding customers believing that they were going to, by default, get a statically allocated range, whatever the length.

If most customers get dynamically assigned (via PD or other means) then the issue is not a major one.

MMC

On 06/02/2009, at 8:56 PM, Paul Jakma wrote:

On Thu, 5 Feb 2009, Matthew Moyle-Croft wrote:

DHCP(v6). Setting the idea in people's heads that a /64 IS going to be their own statically is insane and will blow out provider's own routing tables more than is rational.

Routing table size will be a function of the number of customers - *not* the prefix length assigned to them (for so long as address space is sufficiently sparsely allocated that there's a 1:1 mapping from customer to prefix - which should be "for a long time" with IPv6).

So (within that longer term constraint) it doesn't matter if you're allocating your customer a /48, /56 or /64.

Indeed, what you're suggesting - smaller-than-64 allocations - *would* increase routing table sizes. With your proposal those indexes would increase greatly in depth (and possibly other space increases due to not being able to optimise for "hierarchical routing of bits past 64 is highly rare").

Think of IPv6 as a 64bit network address + host address. At least for now.

regards,
--
Paul Jakma      paul () clubi ie        paul () jakma org       Key ID: 64A2FF6A
Fortune:
If you don't have a nasty obituary you probably didn't matter.
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--
Matthew Moyle-Croft Internode/Agile Peering and Core Networks
Level 5, 162 Grenfell Street, Adelaide, SA 5000 Australia
Email: mmc () internode com au    Web: http://www.on.net
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