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

[James Carlson]

Joe Touch writes:
> James Carlson wrote:
> > 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? 
> 
> No reason. This is fine in that case. The doc should be clear about the 
> potential for silent misconfiguration in those cases.

One possibility would be for implementations that offer this option to
listen to traffic on the links on which default broadcast has been
disabled.  If the implementation sees packets it's not expecting
there, then either raise an alarm or simply turn the option flag back
off automatically in order to preserve correct operation.

That wouldn't be _perfect_, as a quarry of completely silent local
nodes would (as described before) fail to operate completely
correctly, but it may well be "good enough" for general use, given
that most nodes will eventually send some sort of packet once in a
while, if only as a lark, and you just need _one_ to detect the
misconfiguration.

The option proposed is an optimization that reduces duplicate
transmissions ... but does so only for traffic that ought to be (by
design) very low rate; unknown destinations and broadcast.  If it
isn't implemented or if it might automatically turn itself back off,
it doesn't seem like a substantial problem to me, though I suppose
there are a few degenerate large flat networks out there where
broadcast more resembles a shower than a mist.

-- 
James Carlson, Solaris Networking              <james.d.carlson at sun.com>
Sun Microsystems / 35 Network Drive        71.232W   Vox +1 781 442 2084
MS UBUR02-212 / Burlington MA 01803-2757   42.496N   Fax +1 781 442 1677