[rbridge] VLAN mapping anonmolies...does anyone care?

[Radia Perlman]

A couple of things to bring to people's attention in fewer words than 
reading the VLAN mapping draft. :-)

a) if mappings are not invertible, as in, both VLAN A and VLAN B in East 
map to VLAN C in West,
then it's not clear what to map VLAN C to, when forwarding from West to 
East.

I'd say either make that a configuration error and don't let someone 
configure two VLANs that map
to the same thing, or say that when mapping from (West, VLAN C), if both 
A and B from East map to (West, C),
then map to the highest VLAN number, or the first one listed in the 
mapping configuration table. Other
suggestions?

b) if mappings are not invertible, same example as a). and the path goes 
from East to West and then East
again, VLAN A in East might wind up getting mapped to VLAN B in East.

I don't care -- I think noninvertible mappings should be illegal.

c) another form of noninvertible mapping is (East, VLAN A : West, null), 
meaning that VLAN A in East
should be dropped instead of being forwarded to cloud West. The 
surprising result of this, if the path
goes from East to West and back to East, is that VLAN A might become 
partitioned as a result.

I don't care, especially since I can't think of any good, simple 
solution to this.

Radia