RE: Stateless Prefix Delegation I-D updated (draft-savolainen-stateless-pd)

[<teemu.savolainen@nokia.com>]

Hi Conrad,

> I assume you mean specifically section 5 of this draft - the supposed
> problem with DHCPv6 not allowing to assign prefixes backward. This has
> good reasons: DHCP is a forward assignment - assigning part of the
> delegated prefix back to the originating link usually leads to problems
> with routing.

Rather the delegating router would delegate a prefix minus one /64. I.e. the one /64 would not be really assigned back to the originating link, but rather never assigned to requesting router at the first place...

> The solution is to assign a separate portion of the provider prefix to
> direct link prefixes and delegate something different from this. It
> requires a bit more thinking on the network operators part, but causes
> much less pain for the support hotline... ;-)
> 
> Eg. if the provider uses 2001:db8::/32 and has about 10mio customers
> (24bit customer ID) one solution would be to reserve 2001:db8:0::/40
> for
> link assignment and 2001:db8:100::/40 through 2001:db8:ff00::/40 for
> PD.
> As a customer I could for example get 2001:db8:11:2233::/64 via SLAAC
> for
> the uplink and 2001:db8:1122:3300::/56 via DHCPv6 PD for delegation
> downstream.

Isn't this close to what I describe in stateless draft, i.e. having a /32 bit ISP prefix, and then using 24 lowest bits of the /64 prefix given to UE (with SLAAC) in calculating the delegated /56 prefix? In DHCPv6-"light" this calculation would be done by DR, in Stateless this would be done by RR.

Best regards,

Teemu