> [I]sn't the AUI interface a half-duplex device?

Yes, AUI is half-duplex; it is designed for interfacing to shared
broadcast media like 10base5 or 10base2 which are inherently
half-duplex.

However, I didn't see anyone talking about AUI anywhere, so I'm not
sure why that's relevant.

> Another thing I noticed was that if I changed the
> "local-mac-address?" OB env.var. to "true", I didn't get that
> stuttering LED on the switch.

Does the machine in question have multiple interfaces, which are
connected to different sides of the router, or different ports on the
same switch, or any such?

Using the same unicast MAC address more than once within a given ARP
domain (hub, vlan on a switch, etc) is a Bad Thing.  If the switch has
vlans, there is potential for its getting confused by seeing the same
MAC address in multiple vlans.  Such behaviour is buggy, and most
switches these days don't suffer from it, but the potential is there
and depending on how many corners were cut when your switch was made it
could be relevant.

Of course, this is entirely guessing.  I'm just trying to come up with
reasons why setting local-mac-address? true might make a difference.
(This is especially odd because I think NetBSD doesn't pay any
attention to local-mac-address?.)

> Anyways, its working and I learned something, so I'm happy :)

There's that, yes. :-)

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