[rbridge] Consensus Check: Configure ports to disable end stationtraffic

[James Carlson]

Joe Touch writes:
> I'm concerned about the case where an end station moves and doesn't 
> announce itself. There's no requirement in ethernet to do so, and such a 
> station would never be discovered if we don't flood broadcast to all links.
> 
> I.e., the optimization below is a recipe for ARP failure in such cases. 
> I disagree with it.

That "failure" is exactly the intent.

In other words, if you connect an end station to a special internal
network that is intentionally designed by a network administrator
_not_ to have end stations on it at all (which is what this
configuration option specifies), then you've made a mistake, and you
should _expect_ the node's attempts to communicate to fail miserably.

Obviously, the default should be to forward these messages (ports
can't be "TRILL-only" type by default), but why try to prohibit
implementations from offering an option if vendors so choose?  ARP
failure modes for nodes that shouldn't be there at all shouldn't be a
reason for a prohibition.

On the consensus proposal, I don't see a real reason why a description
of such an option needs to be in the spec -- it seems to me that an
implementation could provide such a feature under the guise of a
"local optimization" without needing this group's permission to do so
-- but if it is going to be there as an option, I'd weakly support it.
(Really ... do we think we can outlaw vendor features or that we need
to explicitly endorse each one?)

(I say "weakly" because _every_ option added increases complexity, and
that's one of the important problems.  But if it's somehow crucial,
then ok.)

-- 
James Carlson, Solaris Networking              <james.d.carlson at sun.com>
Sun Microsystems / 35 Network Drive        71.232W   Vox +1 781 442 2084
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