With TCP/IP serving as the de facto network protocol and many legacy networks (another way of saying "old networks") running IPX/SPX, some very fast and clever network protocols have kind of fallen by the wayside. Let's take a look at some other network protocols that you can still use and that will certainly be found on networks running in some environments.
NetBIOS Extended User Interface (or NetBEUI ) is a simple and fast network protocol that was designed to be used with Microsoft's and IBM's NetBIOS (Network Basic Input Output System) protocol on small networks. NetBIOS is a protocol that allows computers to be identified on the network by a friendly name . Anyone who has ever set up a version of Microsoft Windows has experienced setting up a computer name during the installation of the Windows software.
Although it's an excellent transport protocol that doesn't require a whole lot of resources from a computer or the network to move data, NetBEUI is not a routable protocol; therefore, it cannot be used on large networks where routers are used to move data between the various segments or subnets. As far as protocol concepts go, NetBEUI operates at the Transport and Network layers of the OSI model.
With the release of Windows XP, Microsoft no longer supports NetBEUI as a default network protocol. It is not listed when you attempt to add a protocol to the connection Properties dialog box of a computer running Windows XP (or Windows Server 2003). For information on adding NetBEUI to a Windows XP computer see the link http://support.microsoft.com/default.aspx?scid=kb;en-us;Q301041&sd=tech. It provides all the steps for installing NetBEUI as a network protocol.
In the first decade or so of the PC revolution, the Macintosh computer definitely had a leg up on the DOS/Windows environment as far as networking was concerned because of the AppleTalk protocol stack. AppleTalk was (and still is) extremely easy to configure, and the hardware required for network connectivity (called LocalTalk ) was built into each and every Macintosh (Mac computers, including the new iMac, still come with all the networking hardware required; however, their configuration is now slanted toward Ethernet and TCP/IP).
AppleTalk is a routable protocol that allows large networks to be broken into logical subgroups called zones . A zone is a collection of certain users (which do not have to be located at the same physical location) and is similar to the concept of workgroups in Microsoft peer-to-peer networking (we will explore Microsoft workgroups in Chapter 6). Users in a zone typically share the same network resources, such as files and printers.
AppleTalk also uses a two-part network addressing system (as do TCP/IP and IPX/SPX). This address is divided into a network portion and a node (or computer) portion.
The network number is actually specified by the network administrator. Because it is a logical addressing system, decimal numbers can be used to identify the different AppleTalk logical networks that reside on the actual physical network. For example, a logical network that takes up an entire physical network could be assigned the network number 10 by the administrator. If several different AppleTalk networks were to be assigned to one physical network, the administrator could designate them as a numerical range, such as 1020.
Node addresses are extremely easy to configure because you don't actually configure them at all. When a Macintosh client is brought up on the AppleTalk network, it generates a random node number and broadcasts it out onto the network to let the other computers know that it is going to use that number. This serves as the node address for the computer. The logical network number created by the administrator (such as 10, as in the preceding example) and the random node address that is generated by the computer make up the complete network address for the computer.
AppleTalk and the OSI Model
The AppleTalk protocol stack is made up of a number of protocols that supply all the features required for network communication. Table 5.5 provides a list and brief definition of some of the AppleTalk protocol stack members .
Table 5.5. AppleTalk Protocol Stack Members
Before we completely end this discussion of network protocols, I should mention the Data Link Control protocol (or DLC ). DLC was actually developed for communication between mainframes and Hewlett-Packard (HP) printers. You might run into DLC in situations where you have printers directly connected to a network (rather than connected to a computer on the network) using an HP Jet Direct box or HP Jet Direct card. Typically, printers connected using these devices will be assigned an IP address like any other node on the network.
However, if you are using HP Jet Direct-enabled printers on a network that is not using TCP/IP, you must use DLC for the printer or printers to communicate with the computers on the network. DLC can be configured on Windows-based computers. DLC is also configured on the printers using installation software that is provided with the HP Jet Direct box or card.