Читать книгу Networking All-in-One For Dummies - Lowe Doug, Doug Lowe - Страница 28

As I mention in the preceding chapter, a local area network (LAN) is a network that connects computers and other devices that are located in relatively close proximity to one another. Most LANs are contained to a single building, although it’s possible to create LANs that span several buildings at a single site, provided the buildings are close to one another. For the purposes of this chapter, I stick to LANs that operate within a single building and support anywhere from a few dozen to a few hundred users.

LANs exist to connect computing devices such as workstation computers, servers, printers, scanners, cameras, and so on, together. The essence of a network is the physical infrastructure that enables the connections. The infrastructure is similar to the infrastructure of a city. A city’s infrastructure has many physical elements, including roads, stop signs and stop lights, water supply lines, storm water drains, sewage lines and treatment plants, electrical distribution cables, transformers, and much more.

Similarly, the infrastructure of a network consists of physical elements:

 Cables: These run through walls and ceiling spaces, through conduits, between floors, and wherever else they need to go to reach their destinations.

 Patch panels: These allow cables to be organized at a central location.

 Network switches: A switch is an intermediate device that sits between the networked devices that allows those devices to communicate with each other. In a real way, switches are the core of the network; without switches, computers wouldn’t be able to talk.

 Wireless access points: A wireless access point (or WAP and sometimes just AP) lets devices connect wirelessly to the network. Depending on the size of your network and the physical space your users occupy, you may need more than one WAP. Each WAP needs to be connected to the LAN via a cabled switch connection.

 At least one router: A router enables the network to the outside world. The most common use of a router is to connect the LAN to the Internet. However, routers can also be used to connect one LAN to another. I tell you more about routers in Chapter 3 of this minibook.