IPX / SPX protocol stack (from the English i nternetwork p acket e x change / s equenced p acket e x change - packet firewall / serial packet exchange ) - protocol stack used in Novell NetWare networks. IPX protocol works at the network level of the OSI model , provides packet delivery (analogue of IP from the TCP / IP stack ). The SPX protocol works at the transport and session levels, provides maintenance of a communication session and guaranteed data delivery (analogue of TCP ).
History and Application
The IPX / SPX protocol stack has been implemented by the NetWare network operating system , supplied by Novell since 1983 , and is considered the development of the Xerox Xerox Network Systems protocol stack. IPX / SPX was considered optimal for use in local area networks , while TCP / IP was considered more effective for wide area networks .
By the end of the 1990s, TCP / IP, which was the generally accepted Internet stack, effectively supplanted IPX / SPX from local computing environments. The IPX / SPX stack has never been used on wide area networks.
Currently, the protocol is not required for use on Netware networks (starting with versions 4.x) and is supported not only by it.
As of 2011, many operating systems still support IPX / SPX, but support continues to decline.
Initially, the IPX / SPX protocol stack client was developed by Novell for DOS and has been widely used both on corporate networks and for network games. The client was implemented as a resident program . The first implementations required the creation of an executable file for each network card , but in the future the setup procedure was simplified, and it became possible to use ready-made executable modules.
Due to the widespread adoption of IPX / SPX protocols in the 1990s, Microsoft implemented them under its Windows operating system , starting with Windows for Workgroups and Windows NT , under the name NWLink . However, by default, they were used only as a transport for SMB / NetBIOS , and a separate NCP client was required to communicate with NetWare servers. Windows 95 included the base client, but it was not installed by default.
“NWLink” was included in Windows until and including Windows 2003 and was excluded from Windows Vista . The client developed by Novell uses its protocol implementation, although some versions made it possible to use NWLink (with a warning about possible incompatibilities).
For UNIX, there were various implementations developed by both Novell itself and third-party authors. Novell UnixWare had native IPX / SPX support, although it required additional software to support file and printer sharing.
There are also implementations for Linux  and FreeBSD . OpenBSD has dropped IPX / SPX support in version 4.2  .
Sun Microsystems has implemented the IPX / SPX stack for its Solaris OS .
The Novell Open Enterprise Server network operating system (based on the Linux OS ) does not support IPX / SPX.
For several years, Novell has been delivering a client for OS / 2 , similar in structure to a DOS client. She also supplied a client for Mac OS Classic (only for the "classic" versions, from 7.6 to 9.x) under the name "MacIPX".
Cisco Systems IOS provides IPX routing services (currently only in the Enterprise Base edition).
The following protocols are available for IPX / SPX:
- EIGRP (developed by Cisco Systems );
- NLSP (Netware Link Services Protocol) - adapted for IPX version of the network protocol IS-IS  .
- N. Olifer, V. Olifer. The role of communication protocols and the functional purpose of the main types of equipment of corporate networks. IPX / SPX stack . Center for Information Technology ( 1999 ). Date of treatment March 6, 2011. Archived on February 5, 2012.
- TCP / IP