Wireless Performance

I used the new open air test method described here to test the 110's wireless performance. Testing was done using a Linksys WPC100 Cardbus adapter inserted into a Fujitsu P7120 Lifebook (1.2 GHz Intel Pentium M, 504 MB) notebook running WinXP Pro SP2 with all the latest updates. I used the latest Win XP SP2 6.0.3.120 driver and Win XP's built-in Wireless Zero Config client during testing. The router was upgraded to 1.0.04 firmware and I left all factory default settings in place, except to set Channel 1 for the 20 MHz mode tests.

Figure 6 shows a composite of up and downlink throughput tests made at the six test locations in two wireless modes: 2.4 GHz, 20 MHz channel; and 2.4 GHz, Auto 20/40 MHz channel. Each column represents the average throughput from a one minute test.

You can see best-case (Location A) throughput just shy of 40 Mbps in the 20 MHz mode and just over 60 Mbps in Auto 20/40. I confirmed that two channels (1 and 5) were being used in this mode using a Cognio Spectrum Expert spectrum analyzer.

Figure 6: WRT110 wireless performance summary

Figure 7 shows a composite of the actual IxChariot test results running downlink in the Auto 20/40 mode. You can see that the WRT110 and WPC100 actually did work in Location E. But the throughput was so low, the result rounded down to zero.

Figure 7: Six location wireless throughput - downlink

Throughput is generally well-behaved with some evidence of rate-shifting in Location B (the rising "stair steps"). I should note that the Windows XP Network Connection status reported a steady 130 Mbps link speed in Auto 20/40 mode and 65 Mbps in 20 MHz mode. But the plots say that the client driver isn't reporting the actual link rate in use. Uplink behavior was similar, as you can see in this plot.

I also tested for throughput reduction with wireless security set to WEP, WPA/TKIP and WPA2/AES and found a fallback to 54 mode in WEP, with subsequent throughput reduction. Figure 8 shows downlink results; uplink behaved similarly. There is no result for WPA/TKIP because while the WPC100 and WRT110 would associate, the card was unable to complete a DHCP IP lease after multiple attempts.

Figure 8: Wireless security mode throughput comparison - Auto 20/40 downlink

Tags: 802.11n, Linksys, WiFi,

Related Articles: