We expect the QB.11 to fare just as well as its MP.11 brethren. With an integrated 23-dBi gain antenna, the QB.11, priced at $2,999 for the pair, will enable organizations to move beyond WLAN AP-based bridges, without spending a princely sum. How We Tested
To test P2P wireless solutions, we connected each radio using cable and attenuated the signal to reduce the overall signal strength of the link and simulate distance. Attenuation was provided through the use of fixed attenuators from Mini-Circuits, as well as a variable digital attenuator from Azimuth Systems.
We connected each radio by Ethernet to a Cisco Systems Catalyst 3750 switch. Twelve laptop clients (two Hewlett-Packard nc6220s, two Dell Latitude 610s, one Dell Latitude 500, two Toshiba Satellite 1200s and five Lenovo R60s) served as endpoints for Ixia's Chariot performance-testing software; six were connected by Fast Ethernet to the switch on each side of the link. In addition, we connected three 10/100 Ethernet ports from our Spirent SmartBits 600B to each switch.
To test throughput, we used Chariot's throughput. scr script, which repeatedly transfers a 100-KB file for the test's duration. Each laptop transferred data in only one direction to ensure that laptop NICs did not serve as a limiting factor. An equal amount of traffic was sent simultaneously in each direction to determine maximum throughput across the overall link. We ran each test for five minutes in Chariot's "batch" mode with endpoint polling disabled to obtain the most accurate results possible.
We tested QoS by generating 12 simultaneous simulated VoIP calls using Chariot. Our SmartBits 600B's throughput test program generated enough traffic that the link was completely saturated. We determined the link's saturation point using SmartBits' throughput test and by calculating the maximum possible throughput, without any TCP overhead. Once the link was at full capacity, we sent VoIP traffic across and used Chariot to determine the MOS (mean opinion score, an indicator of call quality) with QoS enabled and disabled.
