Speaking on Deep Background, the Press Secretary whispered:
> manufacturer assigned macs are guaranteed to be globally unique.
Theoretically. I didn't experience it personally, but I believe there
was at least one fairly well known event a few years back where a
manufacturer shipped cards with duplicated UAAs.
Ascend had a run of Pipeline ISDN routers where the record stuck
the record stuck the record stuck [1] the MAC incrementor stuck
on the production line.
No one noticed for months until some poor guy had TWO on one
LAN segment...
[1] Apologies to Monty Python..