[rbridge] Time to summarize "forward or block" BPDU thread

[Erik Nordmark]

Joe Touch wrote:

> What exactly are rbridges 'like' if they BLOCK?

I think they would be like IP multicast routers, but operating at L2 
instead of L3. Multicast routers, unlike IP unicast routers, need to be 
concerned with multiple next-hops picking up the same packet. Same issue 
appears for RBridges. The proposed solution for RBridges is what we have 
for multicast (a single elected forwarder).

    Erik