Five Reasons Not To Go Wireless

Wireless makes networking simpler and less cumbersome for many people, but it is not the right choice for every application. Here are five reasons to stay cabled:

1. Usability. A wide variety of wireless offerings are available in the market, including Bluetooth, Zigbee, multiple flavors of 802.11, and proprietary 900 Mhz. Each has its own strengths and limitations. Which is right for you? Are you a discrete operation, or continuous process? If the former, you should stick with 802.11, whereas the ISA 100 standard was written with process industries in mind. On the other hand, most office environments rely on 802.11b or 802.11g. In those cases, using 802.11a may be most appropriate so that the standards do not end up conflicting with one another.
2. Price. Because most PCs now come with built-in Ethernet ports, if you don't need to rip out walls, running cable is less expensive than setting up a wireless network.
3. Security. The issue of security comes up again and again as an objection to deploying a wireless solution, but there is no need for “security by obscurity.” Security methodologies do exist for wireless. It is just a matter of how deep you want to go. For those building an 802.11 network, industry standard wireless encryption methods such as Wired Equivalency Protocol (WEP), Wi-Fi Protected Access (WPA) and WPA2 all provide at the least a base level of protection. Each encryption level incorporates a higher degree of security, thus making it more difficult for someone to eavesdrop on a data communication conversation. However, there are limitations too. For example, the new WPA2 security is better than the original WEP, but WPA availability remains spotty, especially for PCs not running Windows XP. Even an unencrypted wired connection has a measure of security in that a would-be hacker has to gain physical access to the network.
4. Consistency. Some people believe that a wireless application needs to be as reliable as its wired equivalent, but the vote is not unanimous.  This is why it is so important to know your particular requirements, and also remember that reliability can be added to the network later if needed. For many applications, including process-type applications, “pretty good” may be good enough. However, reliability cannot be compromised for most plant-floor applications.  In the shop, most applications are Input/Output (I/O), in which updates need to happen in milliseconds, as opposed to the office environment where you send something to the printer and usually do not care if it takes a few minutes to get there.  Interference can slow down or even kill a Wi-Fi signal, especially in areas where several Wi-Fi networks overlap. This is less of a problem for 802.11a products than for 802.11b and 802.11g networks, which share the 2.4-GHz portion of the spectrum with other devices such as Bluetooth products, cordless phones, and microwave ovens.
5. Bandwidth. Though more than adequate for browsing the Internet on a shared DSL connection or for occasional file transfers, wireless throughput may not suffice for people who must frequently move large files between PCs. There is a reason that gigabit Ethernet is gaining popularity: It offers speeds up to 90 times faster than an 802.11g connection.