Paul,

On Apr 29, 2010, at 8:29 AM, Paul Timmins wrote:
> If you change ISPs, send out an RA with the new addresses, wait a bit, then 
> send out an RA with lifetime 0 on the old address.

Even if this works (and I know a lot of applications that use the socket() API 
that effectively cache the address returned by DNS for the lifetime of the 
application), how does this help situations where IPv6 address literals are 
specified in configuration files, e.g., resolv.conf, glue for authoritative DNS 
servers, firewalls/filters, network management systems, etc.?  See sections 5 
and 7 of 
http://www.rfc-editor.org/internet-drafts/draft-carpenter-renum-needs-work-05.txt

The point here is that if there is a non-zero cost associated with renumbering, 
there will be non-zero incentive to deploy technologies such as NATv6 to reduce 
that cost.  Some folks have made the argument that for sites large enough for 
the cost of renumbering to be significant, they should be able to justify 
provider independent space and be willing to accept the administrative and 
financial cost. While this may be the case (I have some doubts that many of the 
folks using PA space now will be all that interested in dealing with the RIR 
system, but I may be biased), it does raise concerns about routing system 
growth and forces ISPs to be willing to accept long IPv6 prefixes from end 
users (which some ISPs have already said they won't do).

Regards,
-drc



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