Network Components

CHAPTER 2 LAN HARDWARE l l l Upon completing this chapter, you should be able to do the following: Explain how to install, inspect, and test network components. Describe how to make physical connections to networks. Explain the function of a network server. As noted in chapter 1, if the hardware, network software, application software, and cabling were all supplied by the same manufacturer, we would have relatively few problems to contend with when we design and implement a network. The answers to many hardware and software incompatibilities are found in the use of interfaces. These various types of interfaces (bridges, gateways, routers, and so on) allow networks to be compatible with one another. NETWORK COMPONENTS More and more, LANs are becoming part of larger networks. By connecting LANs together, any peripheral device, such as external hard disk, printer, or plotter can be shared by all users of the networks. This makes more efficient use of expensive peripherals. Repeaters can be used to amplify electrical signals; which, in turn, allows transmissions to travel greater distances. Bridges (also known as bridge servers) make it possible to interconnect like LANs; that is, two similar networks. Routers enable networks to communicate using the most efficient path. Brouters combine the functions of a bridge and a router. Gateways (also known as gateway servers) make it possible to interconnect unlike LANs; that is, two dissimilar networks. INSTALL COMPONENTS The installation of network components is dependent on the particular type of component, the manufacturer, and the type of cable being used. When it comes to installing one of these components, read the instructions that are supplied with the component to make sure that you install it properly. Repeaters Repeaters are used to amplify electrical signals carried by the network. They work at layer 1 of the OSI model—the physical layer. (The OSI model was covered in chapter 1.) The function of a repeater is to receive incoming signals (a packet of data), regenerate the signals to their original strength, and retransmit them. Repeaters are used to lengthen individual network segments to form a larger extended network. That is, repeaters allow a network to be constructed that exceeds the size limit of a single physical segment by allowing additional lengths of cable to be connected (see figure 2-l). There is a catch, however. For a repeater to be used, both network segments must be identical-same network protocols for all layers, same media access control method, and the same physical transmission technique. This means we could connect two segments that use the CSMA/CD access methods, or connect two segments that are running under the Figure 2-1.—Repeaters used to lengthen individual network segments. 2-1