[rbridge] VLAN Scoping / MAC Uniqueness

[Radia Perlman]

With IS-IS flooding, an RBridge can't simply scan the information for 
VLAN A and then delete it.
It has to store it, since LSPs have to be flooded reliably, so each 
RBridge would have to keep all
endnode information for all VLANs.

Radia

Caitlin Bestler wrote:

>Radia Perlman wrote:
>
>  
>
>>The advantage of this is that flooding of endnode information 
>>for VLAN A need not be stored by any RBridges except those
>>that attach to VLAN A.
>>    
>>
>
>That line leapt out at me on re-read.
>
>*If* we are going to allow RBridges to have the traditional
>bridge option of using scoped or global MAC address learning,
>then we do indeed have to flood endnode information about 
>VLAN A. This is not so that RBridges that are not part of
>VLAN A can *store* the new endnode information, it is so
>they can *delete* contradictory information.
>
>Alternatively, if we explicitly require scoped learning,
>then any RBridge that is not part of VLAN A cannot have
>contradictory information. Then there would be no need
>to flood endnode advertisements.
>
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