In an earlier post I presented the network throughput results of my tests with the Synology RS-407 NAS and IPerf in various configurations. I had a Windows XP x64 client in the mix with a bad network driver that messed up my test results. During these earlier tests I contacted Synology support about the odd results that I was getting, and the technician suggested that I repeat my tests with a cross-over cable, thus eliminating the influence of a switch.
Since then I got rid of the 64-bit XP installation and reverted back to the 32 bit OS. I was hesitant for a long time about making or purchasing a cross-over cable, because it is so unlikely that I will ever use it again. I got one anyway. I repeated the iPerf tests with various client and server configurations, both with the cross-over cable and my HP switch.
I did not create lab conditions, which means that the tests were done with normal network traffic. For instance, the Synology Surveillance Server running on the NAS was recording a video stream while I ran iPerf. The results should therefore be regarded as somewhat lower than under ideal conditions. The Thinkpad laptop ran on battery during the tests, which may explain the meager results
This time, iPerf produced more meaningful and repeatable results. The take-aways for me are that
- I do get transfer rates of over 500 MBit/sec, but only when jumbo frames are turned on. In fact, throughput with MTU=9000 is generally twice the rate of when jumbo frames are turned off (MTU=1500). Jumbo frames are now turned on for good on all stations that support it.
- My HP switch performs well and it is not a bottleneck. Obviously, when I tested with the cross-over cable there was no traffic other than the Windows remote desktop or an SSH terminal session. With the switch, my network was running with standard traffic. It is possible that when accounted for the video stream from the security camera, the results would have been 5-10% higher, meaning that throughput with the switch would be at least as fast as with the cross-over cable, if not faster.
The results are below. Detailed results are here.