When Apple introduced TCP with MacTCP and Open Transport in System 7 in the 1990s, they needed their file sharing protocol (AFP) to run on both TCP and AppleTalk.
Although this market segment is now much reduced, the technologies developed in this area continue to be influential on the Internet and in both Linux and Apple Mac OS X networking—and the TCP/IP protocol has now almost completely replaced IPX, AppleTalk, NBF, and other protocols used by the early PC LANs.