Is there any special magic involved in getting this to work? I have
two types of switches (Cisco and HP), and two types of NICs (one gsip
and one in an SGI, most likely tigon based). None of them talk to each
other.

The only combination I've had any luck with is connecting two
HP-switches to eachother. I guess this could be a cabling problem, but
I don't really think so; I've tried a number of different Cat5/5E
cables.

Anyone with ideas on what might be wrong?

/Johan