Subject: [rbridge] Global MAC Addresses

From: eric.gray at ericsson.com (Eric Gray (LO/EUS))
Date: Thu, 25 Jan 2007 18:41:30 -0600

Caitlin,

	I think we should probably take this discussion off-line
as the answer I am working on is probably too much information
for most of the people on this list.  In summary for the list:

1) It is actually the concatentation of FID + MAC DA that is
   usually used in making a VLAN bridge forwarding decision -
   anywhere where it looks like VLAN + MAC DA is implied (or
   stated), it may be a simplification - and probably is not
   confusing for many implementers.

2) There are two types of VLAN learning involved in what we
   are talking about - individual/independent VLAN learning
   and shared VLAN learning (both are allowed, neither has 
   anything in particular to do with us).

3) There are trade-offs associated with choosing which mode 
   of VLAN learning makes the most sense for different VLAN
   ID subsets in a VLAN bridging deployment - hence this is
   typically a configuration option (if there is a global
   default, it should be individual/independent learning).

4) Using the VLAN ID (or FID) as part of forwarding decisions
   is not so much about the possibility that a MAC address 
   may not be unique as about the fact that forwarding has to
   be scoped in order to properly support VLANs.

5) I fail to see - even if MAC addresses are not unique -
   either how it is this should result in non-globally 
   unique IPv6 addresses, or how it would be TRILL's problem
   if it did.

--
Eric