[rbridge] PS Issue #3

[Gray, Eric]

--> 
--> #3 IF size is an issue...
--> 	what limits the size? STP/RSTP or broadcast traffic, or both?

Not sure what we mean by "size" here and how this differs from
"scale."

Obviously, an RBridge campus is limited to the size of workable
STP/RSTP solutions only in the fully-meshed connectivity case.
The complete solution may be several times as large given that
STP/RSTP domains exterior to the campus are made smaller.  In
addition, some proposed campus topologies will allow for smaller
STP/RSTP domains even within the RBridge campus. 

Employing multicast routing techniques against L2 multicast, may
allow for a larger broadcast domain as well.  This is especially
true given flooding within RBridge campi will be significantly
less than in a typical 802.1 LAN.

However, the size of the broadcast domain including exterior LAN
segments will ultimately determine the maximum "size" (at least
size measured as numbers of contiguous LAN segments).

--
Eric