Editing IPX/SPX (section)

==Protocol layers==
IPX and SPX are derived from [[Xerox Network Systems]]' IDP and SPP protocols respectively. IPX is a [[network-layer]] protocol (layer&nbsp;3 of the [[OSI model]]), while SPX is a [[transport-layer]] protocol (layer&nbsp;4 of the OSI model). The SPX layer sits on top of the IPX layer and provides connection-oriented services between two nodes on the network. SPX is used primarily by [[client–server model|client–server]] applications.

IPX and SPX both provide connection services similar to [[TCP/IP]], with the IPX protocol having similarities to [[Internet Protocol]], and SPX having similarities to [[Transmission Control Protocol|TCP]]. IPX/SPX was primarily designed for [[local area network]]s (LANs) and is a very efficient protocol for this purpose (typically SPX's performance exceeds that of TCP on a small LAN,{{citation needed|date=June 2011}} as in place of [[congestion window]]s and confirmatory acknowledgements, SPX uses simple [[NAK]]s). TCP/IP has, however, become the de&nbsp;facto standard protocol. This is in part due to its superior performance over [[wide area network]]s and the Internet (which uses IP exclusively), and also because TCP/IP is a more mature protocol,{{citation needed|date=April 2014}} designed specifically with this purpose in mind.

Despite the protocols' association with NetWare, they are neither required for NetWare communication (as of NetWare&nbsp;5.x), nor exclusively used on NetWare networks. NetWare communication requires an [[NetWare Core Protocol|NCP]] implementation, which can use IPX/SPX, TCP/IP, or both, as a transport.