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Network World - Editor's note: This vendor-written tech primer has been edited by Network World to eliminate product promotion, but readers should note it will likely favor the submitter's approach.
With the barrage of data traffic hitting corporate and mobile networks from Wi-Fi-enabled smartphones, iPads and other bandwidth-hungry devices, enterprises and carriers must contend with data volumes that often exceed network capacity and a crowded RF spectrum that is impossible to navigate.
Enterprises and carriers must now rethink their infrastructure architectures from the outside in - with an eye on managing RF spectrum resources (the new wire), and latency and delay that effectively kill multimedia transmissions.
According to industry analysts, data traffic continued to increase across all networks in 2010. Some so-called "superphones" routinely average more than 1GB per month, and by the end of 2010, it's expected that the average U.S. consumption per smart device will be approximately 325MB per month, up 112% from 2009.
Additionally, Cisco's mobile data trends research estimates that 66% of the world's mobile data traffic will be video by 2014 and that mobile video will grow at a compound annual growth rate of 131% over the next five years. If this pans out, it will be a looming problem for networkers.
Meanwhile millions of Blackberry and iPhone users already know that mobile operators have a real problem on their hands from painful first-hand experience. Even where 3G networks are highly developed, demand for connectivity is outstripping supply at an unprecedented rate. The cost of transporting data is rising faster than revenue, and poor user experiences resulting from network congestion raise churn. Now these devices are being brought into the enterprise.
Doesn't 802.11n address the data tsunami?
IT departments must now deal with how to provide secure, fast and reliable access to a whole new class of devices that don't have Ethernet ports. The only way into and out of these devices is 3G or Wi-Fi - neither of which have a strong history of performing well.
802.11n dramatically increases potential bandwidth and seems ideal for wireless access. The problem is realizing this "potential."
802.11n is predicated on MIMO technology that leverages multiple antennas to coherently resolve more information than possible with a single antenna. One technique is spatial multiplexing, where multiple independent data streams are transferred simultaneously within one spectral channel of bandwidth, significantly increasing data throughput as the number of resolved spatial data streams is increased.
802.11n also doubles the channel width from 20MHz in previous 802.11 PHYs to 40MHz. So-called "channel bonding" can be enabled in the 5GHz mode or 2.4GHz if it won't interfere with any other 802.11 or non-802.11 (such as Bluetooth) systems using those same frequencies.
But without explicit knowledge of and control over the RF domain, these techniques are rendered useless. Concurrent Wi-Fi signals can be corrupted during transmission by interference or obstacles, thereby increasing retransmissions, packet loss and delays. If the Wi-Fi system can't select clean channels, bonding becomes hit or miss.