Wireless Networking (Wifi) Guide

  • By David Maloney
  • 09 Dec, 2016
Types of wifi :

Wireless Ethernet, commonly referred to as Wifi, comes in 4 types:

Wifi Type -- RF Spectrum -- Bandwidth -- Throughput

  • Wireless A -- 5 Ghz -- 54 Mbps -- 22 Mbps
  • Wireless B -- 2.4 Ghz -- 11 Mbps -- 11 Mbps
  • Wireless G -- 2.4 Ghz -- 54 Mbps -- 22 Mbps
  • Wireless N -- 2.4 Ghz and/or 5 Ghz -- 60 Mbps -- 130 Mbps

Wireless B was available first, followed very shortly by A. B was inexpensive, but not very fast, nor did it have terribly impressive range. A was designed for business use, and was vastly more expensive, but also significantly faster. When G came out, it offered significantly faster performance, and increased range, compared to both A and B.

A, B and G are currently (May of 2009) all very well-established standards, and the new kid on the block is Wireless N. N offers significantly increased speed and range compared to all the other types of wifi, but it is still not yet a settled standard. Manufacturers have been selling Pre-N and Draft-N devices for several years, but there is still a possibility that there may be incompatibilities between devices from different manufacturers, since the standard is not yet set in stone.

Interference :
Wireless B, G, and N, which all operate in the 2.4 Ghz radio frequency range, can be interfered with by cordless phones and microwaves. I have not seen many instances of either of these causing problems, but the possibility is there. Also (and this is becoming an increasing problem, given the exponential rise in the number of wireless networks in operation), these networks can interfere with one another.

If you suspect that interference is a problem, using Wireless A or the 5 Ghz band of Wireless N is your best bet.

Equipment :
To use a wifi network, you need a PC or laptop with a wireless network card. That wireless network card connects to a Wireless Access Point (WAP).

Many manufacturers make devices that incorporate a WAP into a device that can also do wired and wireless network routing, which makes the device a wireless router.

Inexplicably, many wireless routers are actually less expensive than plain wireless access points, even though they have more functions. With most wireless routers, you can also use them as simple WAPs if you already have a router and don't need a second one. Call us, and we can tell you how to accomplish this.

Encryption :
Over time, it has become increasingly important to secure wireless networks, and several different standard encryption schemes are available.

The first was WEP (Wired-Equivalent Privacy), which used 128-bit encryption, and HEX encryption keys. The WEP encryption scheme was quickly cracked, however, and today a WEP-encrypted wireless network is considered essentially to be not secure at all.

After WEP was defeated, the next scheme was WPA (Wireless Protected Access), which was vastly more secure, and is still a viable encryption method in use today (2009).

WPA-II is also available, which further increases the protection of the network encrypted using that method.

Since encryption is dependent on hardware, some very old wireless network cards, old laptops that incorporate them, and old WAPs can only use WEP, while only the newest can use WPA-II.

Encryption is important because, unlike wired networks, which require someone to come into your office and plug their laptop into a wall jack, with a wireless network, somebody could connect just by being in or near your building.

Once someone connects to your wireless network, they have access to your server, all of your PCs, and they will be able to use your Internet connection.

Manufacturers :
WAPs and routers fall into two broad categories - inexpensive and unreliable and expensive and reliable.

Manufacturers such as Linksys, D-Link, Belkin, Netgear, and many others make very inexpensive WAPs. The problem is that their quality varies widely - not just between manufacturers, or models, but even from one actual device to the other. So one person might purchase a Linksys WAP, and another person might purchase the same model of Linksys WAP; one will have no problems with theirs, and the other person might have to be constantly (daily or weekly) rebooting theirs to make it function reliably. It is entirely possible to get a very reliable device from these inexpensive manufacturers, but there is also a good chance of getting one that is very unreliable - and you never know until you start using it how reliable it will be.

Manufacturers of the expensive but reliable class of WAPs include Cisco, 3Com, and HP/Procurve.

In addition to the reliability factor, the manufacturers of the less expensive WAPs incorporate the latest new technologies into their products as soon as those technologies appear, while the manufacturers of the expensive WAPs typically wait until those technologies are proven. In this case, the technology that is still not yet officially mature is Wireless-N. It is widely used, but still not an official standard. It provides for faster speeds over greater distances.

Conclusion / Recommendation :
If you need an inexpensive WAP, get either a D-Link or a Linksys. They can be had for $150 or less, and will incorporate Wireless-N. If you can afford it, and want to be certain that you will not have to worry about reliability problems, and constantly having to reboot or power-cycle your WAP, go with a more expensive device from Cisco. Those will likely cost in the vicinity of $400.

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