My old Planet XRT-401C router has these ports. My former ISP gave me a cable modem where I have to plug the lan cable from the cable modem to the WAN port. But now I'm switching ISP who provides me with a direct Ethernet cable into my home without a cable modem. By some trial and error I notice that now I need to plug the ISP's Ethernet cable to the Uplink port next to the WAN port.
But what is the technical difference between the 2? Also what is the 5th port labeled Uplink next the port labeled 1 and the what's the meaning of the line connecting the 2? The manual didn't explain any of these!