[rbridge] duplicate-arp equivalence.

[Bill Sommerfeld]

I've looked at rbridges a little bit from the perspective of a host
implementor..

A very desirable property of an rbridge ARP proxy would replicate the
existing arp conflict detection behavior you see on a broadcast
network -- both nodes see both arp replies, and a common response is
to generate a log message along the lines of:

	WARNING: IP: Hardware address '00:90:96:xx:yy:zz' trying to be
	our address 130.129.a.b!

(quoted from a log entry from earlier today on my laptop; edited to
protect the guilty from embarassment).

A collection of rbridges would have to do something special in this
case to notice the address collision -- so, in addition to generating
the duplicate arp replies it could also generate a log message/audit
event/management trap indicating that something odd is going on.

In addition, an rbridge could be in a position to "resolve" the clash
by enforcing its own policy.

(I'd appreciate it if section 7 of the draft could be enhanced to
mention this case..)

						- Bill