From my understanding in terms of connection it is when you can adjust your QoS (quality of service) to give more bandwidth to a specific device or application and lower the bandwidth to others. I'm assuming it's referring to the built in LAN on the motherboard, as most do.
So basically if you want better ping in games while downloading something, you could prioritize the game, or vice versa. This often requires a router that supports the feature as well, however some applications have it built in (such as uTorrent).