Outdated networking protocol made for LANs, and requiring an emulator like Kali for TCP-IP (internet) use. This protocol survived much longer than it should have because of the absence of TCP-IP drivers for DOS. Old games like War2, DooM, Duke3d and early versions of Quake 1 use it. IPX/SPX is much easier to get working on a LAN and its DOS drivers allow slower computers (386s/486s) to join in the fun. (its faster than windows which creates a virtual86 for every app)