Wondering if you've encountered an issue with Cisco Network Assistant v5.4. With the previous version(5.3) I could see and modify all my cisco switches(<40) but after upgrading to 5.4 I only have access to the WS-2950 and the WS-4507R models. I can't reach my WS-C3548, WS-C3550, WS-C3560 and WS-C2924 models. There are various ways you can discover the switches but none work for thoses switches. No error message other than it seems to try forever to reach the switch. All switches operate under Vlan 99 and I can access then via Telnet, ping etc. Does seem to be a communication problem I thought it might have been a IOS issue but I upgraded one of the switches with no luck.

As far as I know you need only have IP connectivity for this to work. If I go back to version 5.3 I can reach all my switches again.