What You Should Know about Wireless LANs to Get a Networking Job - dummies

What You Should Know about Wireless LANs to Get a Networking Job

By Peter H. Gregory, Bill Hughes

As long as you don’t have to go outside of the boundaries of your own property, you can network using LANs. Generally, LAN technology is much cheaper and faster than WAN technology.

The benefits of wireless LANs have been understood for quite a while. Running cable to offices through walls is annoying. Also, workers want to take their laptops and smartphones to meetings and still get emails and access to applications.

Wireless LANs did not gain popularity until the last decade or so. The first standard that caught on was 802.11, announced in 1997 by the Institute of Electrical and Electronics Engineers (IEEE) workgroup on wireless LANs.

The common term for 802.11 wireless LAN is Wi-Fi. This term is licensed by the Wi-Fi Alliance. The Wi-Fi Alliance picks up where the technical specifications leave off by providing a certification process to ensure that elements from competitive manufacturers work together.

This workgroup has since come out with new specifications that serve a wider area and add new frequency bands and, more importantly, higher data rates. Here are the specifications and their nominal data rates.

802.11 Protocol Year of Release Nominal Data Rate (Mbit/s) Indoor Range (ft) Outdoor Range (ft)
802.11 1997 2 66 330
802.11a 1999 54 115 390
802.11b 1999 11 115 460
802.11g 2003 54 125 460
802.11n 2009 72.2 230 820
802.11ac 2013 96.3 115 115

Note several things in this table. First, as with Ethernet, the elements in the system automatically adjust to the fastest protocol. You may put in an 802.11ac system, but if the laptop operates at only 802.11a, the protocol uses is 802.11a, which will limit the speed. Unless you check, you never know the speed at which a given laptop is connecting.

Also, the speed mentioned is at optimal conditions. Your mileage may vary — a lot. Wireless communications are fickle; one moment you may be crawling down the highway and the next you may be screaming down it.

The distance from the antenna is a big factor in the speed that a user will see. The information provided above shows the maximum distance at which the given protocol is designed to operate if there is a line of sight between the antenna and the device. This value is approximate and changes in real time. One solution for offering more complete coverage and avoiding dead spots is to put out multiple access points to serve a particular office space.

Multiple access points work up to a point. It would take an entire book to cover all options and strategies for addressing coverage with wireless LANs.

Although wireless LAN coverage is important, security is more of an issue. Wireless LANs might seem like a security problem waiting to happen. However, a properly implemented wireless LAN can be more secure than some copper wire LANs. The key phrase in that last sentence is properly implemented.

A wireless LAN in an organization as well as in a home should be password-protected. Leaving a wireless LAN unprotected is an invitation for trouble. Some bad people make a habit out of walking around looking for unprotected LANs. They may just use some of your service when you want to use it. More likely, these will try to access your LAN and steal credit card and bank account numbers.

Most systems allow you to enter a password once to access Wi-Fi. The password is then stored on your PC or smartphone for when you want to get on the LAN in the future.