Up until now, the challenges of setting up an effective wireless primary and disaster recovery system have always involved trade-offs between cost, complexity, reliability, and time (such as in licensing). This makes the newest entrant of the technologies discussed in this article, point-to-multipoint (P-MP) radio systems, not only an exciting new development but also Leo’s technology of choice.
P-MP marries microwave radio technology to enterprise and makes delivering technologies of all types faster and easier than ever before. This technology is also becoming widely used as a disaster recovery technology. Indeed, two users we are familiar with, both of which are county governments, have scrapped their AT&T T1s altogether and now use P-MP as the primary technology, with a few T1s held back as the backup path.
Here is how the technology works. P-MP products operate in the 900 MHz; 2.4, 5.1, 5.2, 5.4, and 5.7 GHz frequency bands. Since these frequencies are lower than many microwave frequencies, "wash out" and restrictions on range are not as much of an issue.
Like the other technologies, a variety of interfaces are available, including T1 and Ethernet. Start-up costs are low. We have seen central unit costs as low as $2500 and "per rooftop" costs in the $500 range. Typically a small antenna is installed on the roof (about a foot long and 4 inches wide); or in cases where the range is greater, a small dish about the size of a satellite TV antenna.
Furthermore, the equipment does not require a FCC license and is streamlined, with the radio built into the antenna in the same 12" x 4" x 2’ unit on the roof. It’s incredibly easy to get up and running. Most P-MP platforms also include the most common interfaces that enable them to easily integrate with standard network management tools and systems.
Obviously any system that traverses an airwave should be encrypted. Look for a system that provides security with over-the-air DES (data encryption standard) encryption or AES (advanced encryption standard) encryption capabilities. Take a good look at security when using any wireless solution!
P-MP systems serve numerous enterprise locations of virtually any size and can be used for distances up to 15 miles (24 kilometers). Point-to-point links can traverse over greater distances by augmenting the antennas at both ends (a dish similar to a microwave dish is used in these cases) and in fact approximate the "mountain top to mountain top" links described previously.
Most P-MP systems require line of sight, although some of the ones that use the lower frequencies (such as 900 MHz) do not. The lower frequencies however generally limit throughput to T1 speeds (1.544 Mbs)... if you are lucky.
To summarize, P-MP systems, in the opinion of this humble writer, represent the best trade-off of cost, performance, ease of use, and variety of interfaces available to the enterprise user seeking disaster recovery and network availability.