We have a Cisco 1811W router for our connection to the Internet and multiple Catalyst 2948 and Dell 5324, 5448 switches in our network. We have a single subnet network. I recently unplugged one of the Catalyst 2948 switches from the network and about 5 minutes later our router stopped responding. (I could not ping it's inside interface 192.168.1.1.) I plugged the switch back in, and after a minute I could ping the router again. The switch and router are both plugged into the same Dell switch.
The Router internal IP address is 192.168.1.1. We have NAT, the Firewall and Wireless Interface configured. The Catalyst 2948 configuration IP is 192.168.1.33. We do not use separate VLANs. I don't know a lot about router and switch configuration, but I looked through the configurations on both and didn't see anything obvious. I would appreciate any help to solve this problem.