v6 & DSL / Cable modems [was: Private use of non-RFC1918 IP space (IPv6-MW)]
paul at jakma.org
Fri Feb 6 04:26:30 CST 2009
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
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
Paul Jakma paul at clubi.ie paul at jakma.org Key ID: 64A2FF6A
If you don't have a nasty obituary you probably didn't matter.
-- Freeman Dyson
More information about the NANOG