Subject: [homenet] making homenet-source-routing work with 6204

From: Michael Richardson <[email-masked]>
Date: Wed, 07 Nov 2012 11:20:53 -0500

If the 6204 CPE router is one of GW1/GW2 (lets say GW1), then it won't
be participating in the routing protocol and prefix distribution system,
so the host that is behind R won't get an address from GW1, only GW2.

That means that we only have to worry about hosts on the link (call it
H2) that has GW1 (the 6204 only one), which will get an address directly
From GW1.  Such a host will also get an address from GW2.  As pointed
out by Barbara Stark, LAN requirement L-3 says:

   L-3:   An IPv6 CE router MUST advertise itself as a router for the
          delegated prefix(es) (and ULA prefix if configured to provide
          ULA addressing) using the "Route Information Option" specified
          in Section 2.3 of [RFC4191].  This advertisement is
          independent of having or not having IPv6 connectivity on the
          WAN interface.

so, a host on that link will get poor service when it uses the prefix
From GW1.  Happy Eyeballs will solve that for browsers.

However, the worse problem is that if host H2 uses GW1 for traffic to
GW2, it won't get relayed, but will get dropped.  This, I think is the
major problem we will have.

If the 6204 CPE router is not GW1 or GW2, but rather R, then what
happens depends upon whether we distribute prefixes via DHCPv6 or
OSPFv3.  If DHCPv6, it will get one or more prefixes from one or more
GW1/GW2.  (likely it's been programmed to talk to one upstream ISP)

If we distribute prefixes via OSPFv3, then 6204 CPE router R fails to
get a prefix, and fails to work, and it is thrown out.

-- 
Michael Richardson
-on the road-