About address allocating (IPv6, variable length SLA/prefixes?)

[Brian E Carpenter]

Ole Troan wrote:
> 
> > Architecturally, IPv6 has the equivalent of variable length subnet masks
> > built in. There are really only two boundaries that are not flexible-
> > the boundary between the format prefix and the rest of the address, and the
> > /64 boundary. (The format prefix is in fact variable length, but it is
> > architecturally defined.) So any IGP or EGP design needs to be fully flexible
> > to the left of /64. Subnetting to the right of /64 would be tricky.
> 
> all IGP's and EGP's have to support all prefix-lengths. e.g you
> want to announce host routes, /96 for NAT-PT, etc.
> for that matter, the implementation(s) I know will let you create
> subnets of whatever size you like.

Yes, but there are other problems if you subnet to the right of /64
(autoconfiguration for example). I said tricky, not impossible.

  Brian