Bridging connectivity gaps

IT infrastructure requirements can shift quite suddenly. Say, for example, your company lands several large new accounts at the same time. The sudden influx of sales and account management staff so quickly outstrips your office’s square footage that the only reasonable thing to do in the time available is to look for additional space. That space turns out to be a mile or so down the street. As an IT administrator, you need to get the new location connected to the network as soon as possible.

One option is WAN lines, but they are expensive and often require an unmanageable lead time to set up. Security risks may also be a factor, even for a virtual circuit configuration. Yet another wrinkle might be a mission-critical application, which absolutely requires more than one fat pipe path between the primary and secondary locations. T1s or T3s might suffice for the main link, but what about the backup?

In this expansion scenario, you would sooner or later turn to wireless bridging. A specialty set of products, wireless bridges connect buildings or campuses with bandwidth comparable to that of high-end leased lines.

Most IT administrators have shied away from wireless bridges. Maintaining lasers or microwave installations, and connecting them back to local networks, usually requires a combination of black magic and engineering. Consultant expenses for maintaining long-term infrastructure health can rack up quickly. Moreover, these devices have so far been costly and difficult to configure. And they have taken as long to obtain as it takes a provider to configure a T1 virtual circuit.

Even more critical is the issue of latency. New applications want to use new technologies such as streaming video or VoIP, which require not only goodly portions of fat pipes, but also fast hop transitions with latency measured in milliseconds. Wireless broadband isn’t known for these traits.

But wireless bridges are now coming into their own. Manufacturers have spent the past several years revamping their product lines, claiming to have notably improved ease of use, latency, and especially cost.

To prove their worth, we invited several well-known vendors to the balmy shores of Honolulu to participate in a wireless-bridging shoot-out conducted at the world-famous ANCL (Advanced Network Computing Laboratory) at the University of Hawaii. Four vendors worked up the necessary courage: Adtran, Canon, LightPointe, and Orthogon Systems. Collectively, this foursome represents the three major wireless-bridge media: microwave, RF, and optical.

We then presented the vendors with the following challenge: Implement two fast site-to-site connections, first a short hop across the ANCL parking lot (about 50 feet), which we dubbed our short-haul test, and then a longer, campus-to-campus jump (about 1.2 miles), dubbed our long-haul test.

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Additionally, we added a low-latency test, using VoIP testing tools from Brix and Spirent to ensure these devices could reasonably compete with today’s software requirements. These tools had the sensitivity to not only measure total bandwidth, but also to test traffic latency right down to the microsecond.