[rbridge] How to do RPF checks for bidirectional RBridge trees

[Erik Nordmark]

Dino Farinacci wrote:
>> Will you also agree with me that this technique is useful for  
>> network in
>> a steady state, but does not prevent temporary loops when there is a
>> topology change?
> 
> I agree there will be transient multicast packet looping when there  
> are topology changes.

Dino,

I'm trying to draw an example topology where a change causes a transient 
multicast loop (with an "expected incoming adjacency" check) and I can't 
  find one. Unicast is sooo much easier ;-)

Have you observed temporary IP Multicast loops? (apart from the PIM SM 
ones before ASSERTS where added). What was the topology and change 
necessary to trigger those?

    Erik