Re: Extending a /64

[Philip Homburg <[e-mail]>]

> Right. Take the following solution:
> 
>  - there is no subnet prefix / on-link prefix.  - hosts are assigned
>  single addresses via DHCPv6
> 
> The whole concept of interface-id's then become quite abstract.

Assuming current deployments with shared access links, then in my experience,
a router needs to know the subnet prefix. 

> And you could argue that the concept of interface-id's only exist
> within the constraints of subnet-prefixes and SLAAC.

So I'd argue no, on a shared access link you have, explictly or implictly a
subnet prefix and therefor interface ID's

> Is it a requirement that solutions support SLAAC (or current SLAAC)?
> I would argue no.

In the past some people have argued quite strongly against single addresses
via DHCPv6. 

The lack of addresses problem associated with IA_NA could be solved with IA_PD.

However, if we say that we solve the problem with some combination of IA_NA
and IA_PD, then we have come full circle and solve problem that comes from a
lack of PD with more PD.

That may still work if the lack of PD is at an administrative boundary and
then within the client network we solve the lack of address problem with
IA_PD and IA_NA.