IpX

IPx is a term commonly used to refer to IPX, the Internetwork Packet Exchange, a network layer protocol historically used in the IPX/SPX protocol suite. IPX/SPX was developed in the Xerox XNS lineage and became widely adopted in Novell NetWare networks during the 1980s and 1990s as a primary means of local network communication, with SPX providing a connection-oriented transport service.

Technically, IPX operates at the network layer, with SPX as its reliable transport counterpart. IPX uses its own addressing scheme in which an IPX address consists of a 4-byte network number and a 6-byte node address; a separate 2-byte socket field identifies the upper-layer service on that node. This arrangement supports datagram delivery at the IPX layer and, when SPX is used, reliable, connection-oriented communication between endpoints.

Routing in IPX networks employed protocols such as RIP for IPX, along with various router implementations that bridged IPX to other networks. Gateways enabled communication between IPX/SPX networks and TCP/IP networks, enabling broader interoperability during the transition era.

Today, IPX is largely obsolete in modern networks, having been supplanted by TCP/IP. Some legacy networks and certain embedded systems may still maintain IPX support for compatibility with older NetWare environments. When encountered in contemporary documents, IPx often indicates historical or backward-compatible use of IPX rather than a current networking standard.

In summary, IPx (or IPX) refers to the former IPX/SPX protocol suite used primarily in NetWare environments, characterized by its 10-byte IPX addresses, a separate 2-byte socket for services, and a routing ecosystem that did not become the dominant Internet protocol.