Typically your modem would just be layer 2 and you would have a router connected to the modem. If the router then has free Ethernet ports, your WLC can connect there. However, if you have a PoE switch that hangs off your router to power up AP's, it might be better to connect your AP's and WLC on the switch. At home I have a Comcast modem which a 1941w router is connected to. I have 8 PoE Ethernet ports on the router which I also have a PoE switch that hangs off one of the routers Ethernet port and my 2504 and AP's hang off that switch. I do have another PoE switch that hangs off another port on the router where I have a couple more AP's connected to.
You can setup this many ways and if you had a router that was also a modem, you possible can I guess connect the WLC to that.
Thank you for chiming in and providing more color to this.
This is a home setup that I'm attempting, port 1 on the 2504 controller is connected directly to one of the ports on the Verizon FiOS router, 2 AP's are connected directly to the 2504, one to Port 3, the other to port 4. The FiOS router is doing NAT and the inside subnet is 192.168.10.x. I have configured the AP's with static IP addresses (within the same subnet) and they joined the controller successfully, from a client device I am able to see the one SSID configured and I am able to associate to it via WPA2. The issue is that I'm not able to get to the Internet. Any thoughts? I can post my controller config if it will make things easier.
The DHCP addresses for client devices is coming from the 2504. it is configured as a DHCP server, addresses are in the same subnet as Management interface and also in the same subnet as the FiOS router.