[rbridge] Rbridge port security

[Eastlake III Donald-LDE008]

Hi,

I'm continuing to work through the comments on our first document to hit
the IESG, the routing requirements document.

Based on these, I would say that we have to add a per port configuration
variable for Rbridges that indicates there are no Rbridges connected via
that port. The effect would be that any TRILL frames arriving on that
port would be assumed to be forged and would be discarded. This would
include frames claiming to be core or per-VLAN IS-IS messages as well as
messages that claim to be TRILL encapsulated frames. Of course, the zero
configuration default would be to accept TRILL frames on all ports.

Unless there is some objection, this will be added to the protocol
specification and should probably be mentioned in the architecture
document.

Thanks,
Donald