[rbridge] Ingress Rbridge address and BCN

[Caitlin Bestler]

rbridge-bounces at postel.org wrote:
> If the congestion is detected in the core of the TRILL
> network, how do you signal back to the source host if you
> don't know which is the ingresss RBridge?
> 
> You cannot look-up the inner MAC address, because in the core
> of the network you don't keep the inner MAC addresses in the table.
> Correct? 
> 
> This is a clear reason while you need the ingress RBridge address.
> 

What harm would there be in sending the BCN RBridge encapsulated
with the source-rbridge being the congesting detecting bridge?

Obviously it generates more traffic, but I'm not convinced that
congestion detection by a "core rbridge" that does not already
know of the source will be a common occurrence. The benefits of
adding rbridge functionality are far stronger for the ingress
and egress rbridges.