IPv6 CPE best practices

Thu Jul 16 22:25:00 UTC 2015

In message <[email protected]>, "Chuck Church" writes:
> So, I've been following this IPv6 discussion for a while now.  Putting much
> more thought into it than ever before.  What I've gathered so far:
> 
>  
> 
> We need both SLAAC and DHPCv6 on CPE router to support all end clients.

Yep.

> Android and some other platforms still have some issues with a v6-addressed
> DNS server (or don't use DHCPv6 at all), so you really need your
> v4-addressed DNS server to hand out both AAAA and A records together.  Is
> that close?

Only for really old clients or stupid clients that don't support
both.  DHCPv6 has supported handing out nameserver addresses for
over a decade (2003) so all clients SHOULD support this.  RDNSS was
only defined in 2010.

> So giving each customer a /48 is the way to go.  How does one go about
> configuring CPEs for devices to use this?  I'm aware of how DHCP-PD can dish
> out a /48 of a larger block.

The DHCPv6 client on the upstream interface requests a PD.

> Should I move to a standard CPE that supports
> DHCP-PD (here is a list:  https://getipv6.info/display/IPv6/Broadband+CPE ,
> some mention PD)?  Or should I just allow them to use any IPv6 compatible
> router, and issue each customer a /48, but only configure a /64 of that
> block for each CPE's inside interface (manual config).  Is there anything
> other than DHCP-PD that can do this auto-magically?

The CPE divides the /48 up for local use and further assignment via
PD from its DHCP server.  If there is a CPE to old to do this you
may need to do manual assignment.  Your DHCP server should be able
to do both static and automatic PD.

Also see the homenet IETF working group.  It is working on providing
a standard home route that does this and source/destination based
routing so that homes can have multiple PA prefixes with traffic
going out the correct exit.  There are OpenWrt based routers that
implement this today.

Business class routers may not support fetching the prefix delegation
via PD but they are usually paying you more.

> I support a small WISP occasionally, it's all wireless and Ethernet.
> Several hundred small business customers.  Nothing super complicated.  Been
> playing with an HE tunnel the last few days and found my netflow collector
> works fine with FNF and IPv6, so making some progress.  Just wanting to
> avoid any big mistakes when we think about getting some customers on it.
> 
>  
> 
> Thanks,
> 
>  
> 
> Chuck
> 
>  
> 
-- 
Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742                 INTERNET: marka at isc.org