DHCPv6 Confirm in DOCSIS networks

[Tore Anderson]

Hi,

* John Jason Brzozowski

> Tore your CMTS could be dropping the CONFIRM message. I know of only >
one CMTS that drops this type of message.  The Cisco 10K.

The CMTS has a Cisco MAC address, so it seems likely that this is the
reason why it doesn't work. Thanks - I'll discuss this with my provider.

> The operator probably has two separate DHCPv6 servers running for
> redundancy.  As such, and in the absence of DHCPv6 failover support,
> both servers will send an ADVERTISE.  Does one server have a higher
> preference value than the other?

No preference values are being transmitted in the ADVERTISE messages.
Hmm. I've had my PD prefix change on me once already, and that's the
probably the reason. Unlike my laptop, my HGW (a ZyXEL P2812) sends
RELEASE once its WAN port goes down, and starts the DHCPv6 client state
machine from scratch (with SOLICIT) once it comes back up. So I guess
that would mean it's a coin's toss whether I get back the same prefix I
had before, or if I get the prefix offered by the other DHCPv6 server.
Which is rather problematic, as the ZyXEL doesn't handle LAN renumbering
very well, so I get left with stale and non-working addresses from the
old prefix on the hosts.

Currently I only get only one ADVERTISE message though, so perhaps
they're working on improving this as we speak.

BTW, I found draft-ietf-dhc-dhcpv6-redundancy-consider-02, very useful
work that I'll pass along to my provider, thanks!

Best regards,
-- 
Tore Anderson
Redpill Linpro AS - http://www.redpill-linpro.com/