[rbridge] Ingress Rbridge and FTAG again

[Dinesh G Dutt]

Caitlin Bestler wrote:
> ddutt at cisco.com wrote:
>
>   
>> Ingress Rbridge is essential for multiple purposes especially
>> for troubleshooting and for sending error messages or reports
>> from the middle of the Rbridge core to the ingress Rbridge.
>> Consider for example, the backward congestion notification
>> scheme that is being pursued in IEEE (802.1au). If I want to
>> deploy that work in Rbridges, I need the ability to signal
>> congestion from the middle of the network back to the ingress
>> Rbridge or source end station. If I do not have the ingress
>> Rbridge in the frame, the only way to derive that address is
>> by populating all the edge MAC addresses in the core of the
>> network; this defeats one of the key objectives of an Rbridge, IMHO.
>>
>>     
>
> Are you trying to optimize the sending of the BCN to the source
> MAC address so that the encapsulating RBridge is known without
> having to having stored that information in an intermediate or
> core RBridge?
>   
Yes.
> There is ultimately a need for core RBridges to be able to 
> map source MAC address to source RBridge in order to forward
> a BCN received from an 802.1au bridge that knows nothing 
> about RBridges. So this optimization would be about reducing
> table size and improving latency of BCN relay, rather than 
> about eliminating logic.
>   
Agree, but I don't want the advantages to seem trivial.

Dinesh

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