6. Adding things together

My last set of performance tests were focused on seeing what sort of throughput you'd get in typical use, i.e. the 2521 AP powerline networked to a main router some distance away. I plugged the 2521 into an outlet in my wireless Condition 4 test location, which is upstairs and at the opposite end of my home, and on the other side of the wall of my powerline Condition 4 test location. A 2502 Powerline Ethernet adapter downstairs in my office provided the bridge between the powerline and Ethernet networks.

I then parked my wireless test notebook about 6 feet away from the 2521, i.e. my normal wireless Condition 1 test distance, and ran a 30 second Chariot throughput test. Figure 9 tells the tale.

Figure 9: Best-case wireless connection comparison
(click on the image for a full-sized view)

The lower trace on the plot shows the throughput of the Notebook > 2521 AP > powerline > 2502 > router switch > Ethernet test partner connection, with the upper trace showing the reference "Condition 1" test, i.e. same as shown in Figure 6 above. The results show that the powerline connection is the throughput limiting factor, since throughput is running about equal to the Condition 4 powerline results in Figure 7 above.

As one last check, I left the everything the same, but moved my wireless notebook back downstairs to my office. This was intended to be a powerline plus wireless worst case, adding powerline and wireless "Condition 4" distances together.

Figure 10: Powerline plus wireless worst-case comparison
(click on the image for a full-sized view)

Figure 10 shows that this produced an additional 25% or so throughput reduction (from 3.0 to 2.3 Mbps average), and about a 50% reduction from the wireless Condition 4 test that is included in the plot as a reference. Since the powerline setup is the same, my guess is that this additional throughput loss is due to wireless effects, probably from the slightly different antenna placements.

Keep in mind that you probably wouldn't see throughput this low in a normal setup, since you would have another wireless AP in the "Condition 1" location. Unless your wireless adapter's roaming algorithm were messed up, your wireless connection would be switched to the stronger signal of the closer AP, bringing your throughput back up to the 4Mbps range.

802.11b Wireless Performance Test Results

See details of how we test.