What Does Sequenced Packet Exchange (SPX) Mean?
Sequenced Packet Exchange (SPX) is a sequencing protocol for network packets used with Novell NetWare. Internetwork Packet Exchange (IPX) handles SPX packet forwarding.
NetWare communication requires a NetWare Core Protocol (NCP)-supported transport protocol, such as IPX/SPX, TCP/IP, or both.
Techopedia Explains Sequenced Packet Exchange (SPX)
SPX is primarily used for client/server applications to provide connection-oriented network services similar to TCP/IP. SPX sits above IPX, which is a network layer protocol.
IPX/SPX is derived from Internet Datagram Protocol (IDP) and Sequenced Packet Protocol (SPP), which are Xerox Network Systems protocols that provide routing capability and sequenced and connectionless packet delivery support.