I can't help with much of it, but I can clear up this much.

> MOP DL 8:0:2b:19:8f:4e   > ab:0:0:1:0:0      len   24 code 08 RPR

> The ethernet address shown is the DECServer, I assume ab:0:0:1:0:0 is
> a broadcast address?

I *think* there's only one broadcast Ethernet address,
ff:ff:ff:ff:ff:ff.  ab:0:0:1:0:0 is a multicast address, used for just
this sort of MOP booting.

> What does RPR mean?

#define MOP_K_CODE_RPR          8       /* Request program */

(that from the mopd source).

					der Mouse