Can I use microwave technology to connect two offices?
BY Mie-Yun Lee
An inc.com user asks: I need to network offices located three and ten miles apart. Can I connect them via microwave?
Information Technology mentor Glenn Weadock responds: Yes. The good news is that you have many products from which to choose. That's also the bad news, in that choosing one isn't always easy.
I suggest that you consider microwave and another technology called Direct Sequence Spread Spectrum (DSSS) in the context of other, more traditional options, some of which I discuss here. You will find a fairly linear relationship between data throughput capability and cost, so you can decide how much speed your business can justify buying.
Microwave technology is worth considering, in my opinion, if you require high-speed connections and you have a bunch of money in the bank. Such systems need a line of sight between buildings or a satellite link. You can achieve data throughput rates of 10 Mbps, 20 Mbps, and higher, over a range up to 10 miles (or more with satellite support). However, you will need FCC licenses if you choose this technology. Pinnacle Communications and Digital Microwave are two examples of vendors of microwave systems.
DSSS, another wireless option, is a radio technology that offers data throughput in the range of 1.5 Mbps over a three- to five-mile range, although you can stretch the range to ten miles or so with amplification equipment. Wave Wireless's SpeedLAN is an example of this type of system. DSSS is typically less expensive than microwave, and it uses an unlicensed part of the radio spectrum so you don't need government approval to use it.
Microwave and DSSS are both cool technologies, but don't forget more traditional options, especially if line-of-sight problems or budget constraints place wireless networking out of reach. A T1 line is a digital link that uses two pairs of wires, can handle data, video, and voice, and runs at speeds up to around 1.5 Mbps. (If you can tolerate slower speeds, you can look at a "fractional T1," which is proportionally slower and less expensive.) For slower leased-line connections that are still faster than analog ones, DSL and ISDN lines can represent a cost-effective solution, with many businesses today favoring DSL.
The traditional analog leased line is a fixed point-to-point conditioned phone line between offices. Dial-up links using unconditioned POTS (Plain Old Telephone System) lines are definitely the least expensive connections, but they suffer from fairly severe speed limitations. Today's 56K modems often connect at speeds of 33 kbps to 45 kbps, but you can use a bank of several modems to create multilink connections that go faster.
In closing, I should mention that you don't have to have private, dedicated links between your offices to network them. You can create a private network inside the public Internet. If you already use an Internet service provider, you can use those connections to create a secure "tunnel" of communication that serves your company. Such links constitute a "virtual private network," or VPN. You can set up a VPN with readily available software, such as Windows NT or Windows 2000. Network communications over a VPN are encrypted so that other Internet surfers can't see your VPN traffic.