Internet Packet Exchange (IPX) / Sequenced Packet Exchange (SPX) are network protocols used by Novell NetWare operating systems.  IPX and SPX both provide similar connections services like TCP/IP.  IPX is having similarities to IP and SPX having similarities to TCP.   IPX/SPX are developed primarily designed for local area networks (LANs) and is very efficient protocol for this purpose(typically its performance exceeds that of TCP/IP on LAN).