Determining the network connection link speed

Question

How do I programmatically determine the network connection link speed for an active network connection - like Task Manager shows you in the Networking tab? I'm not really after the bandwidth available, just a figure for the current connection, e.g. 54Mbps, 100Mbps etc.

Answer 1

In the end I found the Win32_PerfRawData_Tcpip_NetworkInterface WMI class, as I need to support legacy platforms which, unfortunately, the Win32_NetworkAdapter doesn't do. Win32_PerfRawData_Tcpip_NetworkInterface has a CurrentBandwidth property which gives me what I need on all required platforms (I realise I said I didn't need "bandwidth" but its acceptable and appears to return the "nominal bandwidth" of the adapter anyway).

Thanks to all those who posted, pointing me in the right direction.

Answer 2

Win32_NetworkAdapter WMI class can help you (Speed property). It returns the value 54000000 for my WiFi adapter connected to a WiFi-g access point.

Answer 3

.NET way how to know adapter speed is

IPGlobalProperties computerProperties = IPGlobalProperties.GetIPGlobalProperties();
NetworkInterface[] nics = NetworkInterface.GetAllNetworkInterfaces();
if ( nics != null )
    for (int i = 0; i < nics.Length; i++)
        Console.WriteLine("Adapter '{0}' speed : {1}", nics[i].Name, nics[i].Speed);

Some adapters are tunnels, so their speed will be returned as 0. Read NetworkInterface documentation on the MSDN for more information.