Things You'll Need
Instructions
Connect one Ethernet cable to the modem's Ethernet port and the uplink or WAN port on your router.
Plug the second Ethernet cable into one of the LAN ports on your router and your computer's Ethernet port.
Insert the third Ethernet cable into one of the LAN ports on your router and the Ethernet port on the back of your Xbox 360.
Turn on your Xbox 360 and choose the option to connect to Xbox Live. Follow the instructions on the screen to complete the registration.