Re: [v6ops] New Version Notification for draft-naveen-slaac-prefix-management-00.txt

[Mark Smith <[e-mail]>]

On Sun, 25 Nov 2018 at 17:16, Mikael Abrahamsson <[e-mail]> wrote:
>
> On Sat, 24 Nov 2018, Templin (US), Fred L wrote:
>
> > Do you think we should bring back RAAN?
>
> Yes, but also note that the relay behavior is my least concern with the
> DHCP+RA combination. The ships in the night problem between leasetimers
> (DHCP) and lifetimes (RA) is a much bigger concern for me.
>

(I haven't followed this thread, apologies if it has been covered.)

In this scenario, I assume the DHCPv6 server is selecting the prefix
to delegate, and the BRAS is acting as a DHCPv6 relay, which is why
the BRAS has to glean the delegated prefix to then be able to announce
it into the routing domain? Are the delegated prefixes dynamic or
static, and if they're static (or at least stable across
disconnect/connect), is it correct that the CPE's DUID is being used
to re-issue the same delegated prefix?

The reason I ask is that the IPv6 residential broadband deployment I
worked on achieved this without gleaning via two methods:

- for static delegated prefixes, the prefix is supplied as part of the
RADIUS authentication response, which the BRAS DHCPv6 server then uses
for DHCPv6-PD, and the BRAS can then announce into the routing domain

- for dynamic delegated prefixes, the RADIUS server provided a pool
name to allocate from, with each BRAS having a local pool with that
name. At the time the pool name was a proprietary RADIUS attribute,
however there is now an IETF attribute for the pool name specified in
RFCRFC6911.


An alternative idea, although probably more medium term, would be to
have the CPE's receive the prefix via DHCPv6-PD, and then the CPE
advertises the prefix itself, using automatically established eBGP
sessions via a well known Link-Local anycast address.

"IPv6 Formal Anycast Addresses and Functional Anycast Addresses"
https://tools.ietf.org/html/draft-smith-6man-form-func-anycast-addresses-00

"5.7.3.  Automatic eBGP Session Establishment"
https://tools.ietf.org/html/draft-smith-6man-form-func-anycast-addresses-00#section-5.7.3


Regards,
Mark.


> --
> Mikael Abrahamsson    email: [e-mail]
>
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