[rbridge] Ingress Rbridge and FTAG again
Dinesh G Dutt
ddutt at cisco.com
Wed Oct 18 11:14:15 PDT 2006
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?
> 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.
We make our world significant by the courage of our questions and by
the depth of our answers. - Carl Sagan
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