What is Internet Packet Exchange (IPX) and How it Works?


IPX or Internet Packet Exchange is a protocol used for routing packets from one network to another by the internetwork. IPX being a Novel NetWare layer protocol offers connectionless services for Token Ring, Ethernet, and data-link protocols. IPX is a commonly used LAN or local area network protocol on the legacy NetWare LANs but was replaced with TCP for the NetWare 5.x.

Internet Packet Exchange

Internet Packet Exchange is a network layer of the IPX/SPX protocol & SPX is a transport layer. More so, IPX has the same function as IP protocol and tells how data is received and sent between the systems. On the other hand, the SPX protocol will be used to maintain and establish the connection between various devices. Both the protocols together are used for creating the network connection & transfer data between the systems.

In the connectionless communications, protocols don’t need any kind of acknowledgment for every packet sent. The packet acknowledgment also called connection control, should be given by the protocols over IPX, like the Sequenced Packet Exchange protocol. As IPX doesn’t properly support any concept of the connection and reliable delivery, this will be used in the situations where guaranteed service isn’t needed or where the occasional lost packet isn’t important.

How Does IPX Work?

IPX packets make use of 32-bit (or 4-byte) numbers to identify every data link uniquely (connected network) in the IPX internetwork. The administrator of every network assigns such network numbers that should be different for every connected network; and all nodes on the connected network should have the same network number.

The nodes find their network number just by communicating with the routers that are attached to a local network. The routers make use of the network numbers and route IPX packets over one network of another within the internetwork. Thus, IPX is the routable protocol. Sometimes, IPX uses 48-bit (or 6-byte) of addresses for every node within the given platform or network.

The whole IPX network address will be 4+6 = 10bytes long. And IPX packets will be assigned 16-bit (or 2-byte) number to identify this networking service that they’re communicating with – like, Network Control Protocol, Service Advertising Protocol, and Routing Information Protocol. Therefore, following 12byte triple identifies this networking service that packet will be communicating.

If the Novel NetWare server is not located on a connected network, then the router informs their client of the nearest server availability based on the cost of their connection. The router is quite familiar with such information as NetWare servers by using IPX to notify their presence network by using SAP that allows the IPX routers to build server tables as per SAP numbers.

Addressing the Right Network

Like noted, network, socket, and node addresses for the destination and source will be held in a header of an IPX packet. Network addresses will be assigned during the NetWare server installation & configuration procedure.

Network node addresses generally come from permanent numbers burned in every Network Interface Card by its vendors. Socket addresses generally come from processes running in the software on every computer. Complete 12byte address of every IPX packet is the hexadecimal number, which takes a certain form.

Coming towards the Benefits

  • IPX/SPX was mainly designed for the local area networks and is efficient when it is used for this purpose only.
  • IPX addresses include local MAC address when compared to the “address assignment” with IPv4.
  • IPX has a bigger address space of 48 bits than 32 bits present in IPv4.
  • No BootP and DHCP in IPX.

Are there any Disadvantages?

  • These days IPX is going out of trend and TCP/IP is mainly used due to the superior performance on wide area networks as well as the Internet and is mature protocol made with the same purpose. The real benefit of the TCP/IP is vendor-independent standards and interoperability.
  • Encapsulating & encrypting the IPX frames in the IP packet needs costly hardware than doing the straight IPSec VPN.
  • With the IPX applications and use of the internet, costs will be higher when implementing VPNs.

Final Words

Are you satisfied with your question? If you are a bit more curious and want to become self-sufficient, you must start learning more about Data Structures and Algorithms, and that also the right way.


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