Wireless video, which generates much higher traffic volumes than voice, requires special consideration as well. Although we don't see enterprises deploying Cisco's TelePresence over Wi-Fi anytime soon, video-based corporate training and closed-circuit television for both inside cameras and those mounted in the parking lot are here now.
Not all apps can be neatly siloed into voice, video, and data. Environmental controls and security monitoring can also be performed wirelessly, eliminating time-consuming and expensive installations. Services such as location and presence increase productivity and security. We're in the midst of a Rolling Review covering location systems, and we like what we see; check out our findings on our Rolling Reviews page.NEED FOR SPEED
Throughput is the first consideration when it comes to network connectivity, and 802.11n delivers: Both vendor and independent tests have shown that peak rates upward of 130 Mbps are achievable in good conditions. Advanced antenna designs, spatial streams, and multiple input/multiple output (MIMO) technology mean 11n also offers better coverage and improved radio frequency reliability and consistency. Access points can be spaced farther apart, if desired, but the better signal may more effectively be used to achieve higher access rates. Multipath, which previously degraded signal quality, is now used to good effect by MIMO to reduce the effects of fading and interference.
There are other benefits of 802.11n. First, it's essentially the fourth generation of the 802.11 standard, yet despite the evolution, each revision is backward compatible on both clients and access points, albeit at lowest common denominator rates. Companies can upgrade gradually because 802.11n clients work with 802.11a/b/g APs, and vice versa.
Second, as the market developed, amendments have been added to address deficiencies in the original 802.11 specification. The most significant are 802.11i, which deals with security, and 802.11e, which introduced quality-of-service features. Architectural approaches also have broadened. First-generation access points were standalone, with little to assist IT in terms of scalability, RF management, and Layer 3 roaming. Startups generally swung to the opposite extreme and centralized everything, leading to what pundits called "thin" APs.
With development of 802.11n and its higher traffic rates, a more sensible distributed approach, first used by Colubris in 2005, has evolved. The management plane remains centralized, as is common in any enterprise service framework, but the control and data planes can be placed at the core, edge switch, or access point. Motorola calls this "adaptive AP," while Trapeze has taken the moniker "Smart Mobile." Even Aruba, with its emphasis on centralized data flows, provides flexibility as described earlier with its Mobile Remote Access Point. Even if the WAN link is interrupted, connections stay up and local traffic will continue to be switched locally.
