NW's new 802.1n stress test

The behavior of 802.11n networking gear is the focus of our latests Network World Clear Choice Tests, a major achievement by David Newman. Using VeriWave's WLAN testing platform, Newman subjected 8 access points from each of four WLAN vendors to a large-scale, public, stress test designed to show their behavior and performance under varying loads. The entire test report is revealing, starting with that the fact that only these four vendors accepted our invitation to participate: Aerohive, Bluesocket, Motorola (the former Symbol Technologies product line), and Siemens [see the tested gear on this eight-image slideshow]. The big ones -- Aruba, Cisco, Trapeze -- all proved gun shy and none of them gave convincing explanations for their refusal to put their products on the line. Overall, results showed 11n could deliver data rates of 250Mbps or more per access point. But power requirements varied widely: Siemens proved especially power efficient, but others may require a range of power upgrades to existing network infrastructures. To me, one of the most intriguing parts of the test showed the performance differences, and the impact of latency, in how the access points handled big, medium, and small frames running upstream, downstream or a combination of those directions. For one thing, this information can be used by IT staff to more closely press vendors for details on how the vendor tested his product. Secondly, Newman says the differences may be due to an array of system-level decisions, ranging from the choice of CPU, the related firmware, limitations in internal bus capacity, direct memory access transfer capacity, memory optimization and so on. Those decisions can have a big impact on how 11n performs under heavy, varied, two-way traffic loads. In the test report and data, Newman shows throughput in both bits and frames per second, to show the effect of packet-processing limits. "With short frames – which are the most common type on enterprise networks, mostly because of TCP acknowledgements – frame rates varied widely between vendors," he writes. Links to some other 11n-related content on our site: Key Considerations for a Successful 802.11n Deployment, by consultant and NW blogger Craig Mathias [Webcast, quick registration required] Our updated Wireless LAN Buyer’s Guides and other resources Analyst endorses Siemens' 802.11n power claims From September 2007: Does 802.11n spell the 'end of Ethernet'?

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