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Legacy Network Protocols

IPX/SPX, NetBEUI, and AppleTalk are older protocols that for the most part have been superseded by TCP/IP. However, you may find these protocols still in use on some older networks, so it is helpful to know a little background about these protocols.

IPX/SPX

The Internetwork Packet Exchange (IPX) protocol was developed by Novell for one of the earliest network operating systems with server capabilities, called NetWare. NetWare was originally ­developed for Ethernet bus, token ring, and ARCnet networks that employed one file server. ­ARCnet is an early proprietary network alternative that uses specialized packets with tokens and that employs a star-bus hybrid network design. Today, NetWare has been replaced by­ Novell Open Enterprise Server that can be installed with a NetWare kernel or a SUSE Linux Enterprise Server kernel. A kernel is an essential set of programs and computer code built into a computer operating system to control processor, disk, memory, and other functions central to the basic operation of a computer.

Along with IPX, Novell developed a companion protocol called Sequenced Packet ­Exchange (SPX) for use with software applications, such as databases.

IPX/SPX was commonly used on earlier NetWare servers through version 4. When Novell issued NetWare 5, users were encouraged to convert to TCP/IP. Today, TCP/IP is the protocol of preference for Novell Open Enterprise Server installations.

Although it is an early network protocol, one advantage of IPX over some other early protocols is that it can be routed, meaning that it can transport data over multiple networks in an enterprise. A disadvantage is that IPX is a “chatty” protocol, because live stations using IPX frequently broadcast their presence across the network. When there were multiple IPX-configured NetWare servers on early networks and several hundred clients, the IPX “I’m here” broadcasts could amount to significant network traffic.

NetBEUI

Early Windows Server networks used NetBIOS Extended User Interface (NetBEUI) as the native protocol. NetBEUI was developed by IBM and Microsoft for LAN Manager and LAN Server before the creation of Windows NT. It was later implemented in the first versions of Windows NT and was also available in Windows 2000. NetBEUI is not supported in Windows XP, ­Windows Server 2003, or any higher Windows versions and has disappeared from modern networks. ­NetBEUI proved to have some significant drawbacks because this protocol cannot be routed and can cause unnecessary traffic.

AppleTalk

Apple developed the AppleTalk protocol suite to network Macintosh computers running the Mac OS operating system. AppleTalk is a peer-to-peer network protocol, which means it is designed to enable Macintosh workstations to communicate regardless of the presence of a server. AppleTalk Phase I was released in 1983. AppleTalk Phase II came in 1989 and was designed to handle an increased number of networked computers and to be interoperable with large heterogeneous networks that host multiple protocols.

AppleTalk is supported by Mac OS systems up through Mac OS X version 10.5 (Leopard). Starting with Mac OS X version 10.6 (Snow Leopard) AppleTalk is no longer supported. An advantage of AppleTalk Phase II is that it works well for communications between ­Macintosh computers, as it is specifically designed for this purpose. Two other advantages are that it is a routable protocol and that it supports multiple logical networks on one physical network through one network interface card (NIC) per computer. As many as 253 nodes can be supported on a single logical network. A disadvantage of using AppleTalk is that it is not as ­effective as TCP/IP for communicating with non-Macintosh computers and AppleTalk is not used on the Internet.


Published on Tue 27 March 2012 by Alistair Pinter in Networking with tag(s): protocols