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

["Konrad Rosenbaum" <konrad@silmor.de>]

Hi,

On Sat, February 27, 2010 23:29, teemu.savolainen@nokia.com wrote:
> Have you seen also
> http://tools.ietf.org/html/draft-krishnan-intarea-pd-epc-00 ? With DHCPv6
> PD there's the issue of not being able to use one /64 on the WAN from the
> delegated space. On the other hand, not having a global /64 prefix on the
> WAN at all (unnumbred model) probably would be too big change for the
> 3GPP. Any thoughts about this issue?

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.

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.



    Konrad