I asked "Are you saying that multicast drops unreachable machines automatically?", to which he replied "No,", so I concluded a connect/disconnect mechanism would be needed (to avoid unnecessary traffic). If something's isn't correct, talk about the issue. { Resorting to personal attacks }--

The more I read about it, the more I think his answer (and thus my conclusion) is wrong, but I haven't found a definitive answer yet.

If you have something relevant to say, either answer the pending question or explain what you disagree with.

Update: Added 2nd and 3rd para.