RE: Multihoming by IP Layer Address Rewriting (MILAR)

[Ramakrishna Gummadi <ramki@cs.berkeley.edu>]

> You've mentioned multicast problems before. Maybe I'm uninformed on the
> subject, not having done any real multicasting, but I don't see the
> problem.
>
> Isn't multicast addressing and routing pretty much independent from
> unicast addressing and routing? What are the problem areas?

No, multicast trees are typically (PIM, etc.) built from corresponding
underlying unicast routing entries, which means that, for example, in
source-specific multicast, a client cannot
connect to a multicast tree using a different unicast source address than
the one the multihomed multicasting source is using.

Another problem is that, due to danger of "ack-implosion", it is typically
not possible to generate any path management messages (like what SCTP
does), and discovering source failures can take a long time.

Finally, multicast security (spoofing, DoS, etc.) is still very immature.

regards,
ramki