A few months ago I wrote about not letting the phone company’s disasters become yours and about ways to protect against the all-too-prevalent cable cut. Many wireless technologies offer a solution to this problem since it is exceedingly difficult to dig up air the way one can dig up a cable. Wireless technology not only increases network availability but it can also help you recover in a disaster.
This month, I provide a few "tricks of the trade" to bolster both benefits to your organization.
Wireless technologies that are useful to the enterprise user for network diversity and disaster recovery include the following:
- Unlicensed point-to-multipoint systems
Each has its own inherent strengths and weaknesses and the application for the technology you choose to back up (voice, bursty data, Internet, and so on) will also play a role in which wireless technology is best.
Following is a brief summary of some common wireless alternatives.
Infrared (Point-to-Point) Links
Point-to-point infrared links are not radio: they are invisible light. You can think of them like the infrared remote for your TV. Infrared is inexpensive, it does not need to be licensed, and infrared equipment comes with a variety of interfaces including T1 and Ethernet. All pretty good advantages to start.
Infrared requires line of sight; that is, one end must be physically visible to the other end of the link. And because it is actually light and not radio, Infrared is much more easily affected by fog, rain, snow, birds, and (practically speaking) anything that will interfere with prorogation of light.
Despite its limitations, infrared is widely used. The equipment can easily be mounted in a building, it does not require any special power or "environment," and its transmitter/receiver can operate through window glass with few problems. If you have an application that requires you to get a T1 across the street or across a small campus, infrared may be your least expensive solution.
Infrared links are also often used for LAN interconnection in buildings that are in close proximity but separated by public rights of way (such as streets) where cabling between buildings is impractical. If you consider the use of an infrared link yourself, be sure you don’t exceed a mile or so (less if you are prone to periodic fog or heavy rain), and that you have clear line of sight.