IPX

Internetwork Packet Exchange (IPX) is the OSI-model Network layer  protocol in the IPX/SPX protocol stack.The IPX/SPX protocol stack is supported by Novell's NetWare network operating system. Because of Netware's popularity through the late 1980s into the mid 1990s, IPX became a popular internetworking protocol. Novell derived IPX from Xerox Network Services' IDP protocol.IPX usage is in general decline as the boom of the Internet has made TCP/IP nearly universal. Computers and networks can run multiple network protocols, so almost all IPX sites will be running TCP/IP as well to allow for Internet connectivity. It is also now possible to run Novell products without IPX, as they have supported both IPX and TCP/IP since NetWare reached version 5.
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IPX

Abbreviation for Internetwork Packet Exchange. A proprietary LAN protocol.

Internetwork Packet eXchange

INTERNETWORK PACKET EXCHANGE [NOVELL]. IPX