Netgear GS605 v2 is faulty!

I have two of these switches, and I just got stung by a nasty hardware fault that is present in version 2 of this device: when you have two of these devices connected to each other (or just on the same LAN), the throughput for all connections on one of them will drop to a few hundred Kb/s e.g. 400Kb/s! This effectively cripples the LAN which should normally have file transfer speeds of > 25Mb/s.

This has been reported on the Netgear forums here and Netgear have acknowledged the fault. Unfortunately there is no solution other than replace one of the devices with something else (apparently v3 of the GS605 works ok), but I learned a few tricks for how to diagnose network bandwidth issues in the process:

  • Use iperf.exe. This is the standard command line app for testing network bandwidth, and work on both linux and Windows. On linux just sudo apt-get install iperf, on Windows download from here.

    It’s easy to use: on one machine, start a server using:

    iperf -s

    On another start a client duplex test to the server using:

    iperf -c [server ip address] -d

    The results will be printed after a few seconds.

  • Use a good Cat5e or Cat6 ethernet cable. Cables can easily be faulty, check for green lights on your NIC & switch port to indicate 1000Mb/s (gigabit) connection speed.
  • Avoid PCI Gigabit cards (use onboard Gb NIC). PCI but is limited, especially if you have any other devices on the bus.
  • Use a decent file-copy utility. For example, SuperCopier, that instantly shows you your copy speed.