Internetwork Packet Exchange (IPX) is at the Network layer of the OSI model and is part of the IPX/SPX protocol stack.
Novell built on top of DEC and Xerox's XNS protocol, and is largely responsible for the use of IPX as a popular computer internetworking protocol as a result of its large marketshare of Network Operating System software (Novell NetWare) in the late 1980s through mid 1990s.
IPX usage is in general decline as the boom of the Internet has made TCP/IP nearly universal. Computers and networks can run multiple network protocols, so almost all IPX sites will be running TCP/IP as well to allow for Internet connectivity. It is also now possible to run Novell products without IPX, as they have supported both IPX and TCP/IP for a few versions now.
Guidelines for Assigning IPX addresses:
- Logical networks must be assigned a unique network address. The address must be a 4-byte or 32-bit value that is unique throughout the entire network. The address number is hexidecimal in the range of 1 - FFFFFFFE.
- Devices on a logical network must have a unique node address. This must be a 6-byte or 48-bit value derived from the MAC address of the NIC in each device.
- Loss of data must be prevented, therefore network addresses must be planned as part of the initial implementation.