[geeks] Switch incompatibilities

[David Passmore]

I'm at my wits end here.

I have a Cisco Series 3500 XL 24-port switch, and an SMC EZ Switch 10/100
5-port, and I want them to talk. They both support IEEE 802.3x,
autonegotiation, simple enough I thought.

Both switches show 100 megabit, full duplex link. Cisco says the port is
up/up. I can ping IPs on the other side of each switch, and the Cisco shows
MAC addresses. I can sniff the network and see ARP broadcasts. 

But I can't see any IP whatsoever. Pings don't work. Nothing which is IP
seems to work. I've tried turning off spanning tree. I've tried hardcoding
speed and duplex on the Cisco switch to every possible combination. I've
powercycled everything. No avail. I get link, and everything says it
*should* work, but it doesn't.

Help?

David