Components of a Simple LAN

In this case, the LAN consists of some obvious elements. First, you need at least two computers. The computers need to have networking software; otherwise, they will never attempt to communicate. They also need the physical ability to transmit bits from one computer to the otherhence the need for the cable and the NICs in each computer. (Figure 4-1 shows the NICs outside the PCs so that you can see them, but they are typically inside the PCs.)

LANs do not get any simpler than this one. Larger LANs can get much more complex, with lots more components like networking hubs and switches, which you will learn more about in the next few chapters.

In this chapter, you learn about how computers can transfer bits across the network roadway. The topics covered here might be the equivalent of what a DOT engineer might talk about over lunch with a stranger: "Hey, you know we're going to be paving Parker-Puckett Parkway pretty soon. Pretty cool, huh?" The reply, "Hey, isn't that near that Mexican place, La Frontera?" And the response from a true DOT engineer: "I don't knowdon't care. That's beside the road. I just care about the road." Likewise, some network engineers think of the LAN as the cable, possibly the NICs, but they typically don't care a lot about the computers that happen to be connected to the cabling. Likewise, this chapter focuses more on how computers send bits to each other, rather than the applications that run on those computers.