Re: multi-homing vs multi-connecting

Christian Huitema wrote:
> Depends what you call classical IPv6. If you throw in the support for
> "binding update", then IPv6 does a reasonable job at "host
> multi-homing",

Well, depends what you mean with reasonable.  With the new
security design, mandated by the desire to make MIPv6 to work
without security infrastructure, MIPv6 always generates some
signalling load.  That is, if a host is away from home, it
must keep sending signalling packets to all its active peers
to maintain the mobility state.  By default the state must be
refreshed about every five minutes.

Furthermore, I don't quite find the requirement of having a
separate home agent, i.e. a piece of infrastructure, as a
reasonable design for multi-homing.

> and I believe that we only need a limited amount of
> additional work to support "small site multi-homing"; essentially, you
> have to get around egress filtering.

Another difficulty is associated with the home agents, too.  If
a home agent is unreachable, the mobile node also becomes unreachable
as soon as it needs to refresh the mobility state, i.e., in about
five minutes.  Thus, you can't simply put a home agent in the
"small site multi-homed" network, that just doesn't work if the
home agent becomes unreachable due to a link failure.

Thus, IMHO, the signalling load and the requirement of having the
home agent always on-line make MIPv6 not-quite-reasonable as a