Detecting a 3G connection in Windows 7 and 8 in a desktop application

Hi

I am in the process of developing a cloud backup software. The application is a desktop application developed using C#.

I need to add an option to stop/pause the backup if the computer was connected to a 3G network to save cost for the user.

I cannot seem to be able to find any example on how this can be achieved, there are some examples for Windows Phone and Windows Store Apps but I cannot find anything that can check if the connection type is a WiFi/Ethernet or 3G the latter is my main concern.

I tried a test application to enumerate the networks:

Code:

---

Console.WriteLine("checking network interfaces\n");

NetworkInterface[] interfaces =  NetworkInterface.GetAllNetworkInterfaces();

foreach (var networkInterface in interfaces)
{
  Console.WriteLine("Interface Detected");
  Console.WriteLine("Description: "+networkInterface.Description);
  Console.WriteLine("ID: " + networkInterface.Id);
  Console.WriteLine("Name: " + networkInterface.Name);
  Console.WriteLine("Interface Type: " + networkInterface.NetworkInterfaceType);
  Console.WriteLine("Operational Status: " + networkInterface.OperationalStatus.ToString());
  Console.WriteLine("Speed: " + networkInterface.Speed.ToString());
  Console.WriteLine("Supports Multicast: " + networkInterface.SupportsMulticast.ToString());
  Console.WriteLine("#########################################################\n");
}

---

The above code list my 3G connection as PPP which can be either ADSL or 3G. I am not sure if I can differentiate using some other options or APIs.

I need a clear way to distinguish between those networks and so far I cannot find a way of doing so.

Can someone please help?