How to get accurate download/upload speed in C#.NE

Question

I want to get accurate download/upload speed through a Network Interface using C# .NET I know that it can be calculated using GetIPv4Statistics().BytesReceived and putting the Thread to sleep for sometime. But it's not giving the output what I am getting in my browser.

Answer 1

Here is a quick snippet of code from LINQPad. It uses a very simple moving average. It shows "accurate speeds" using "Speedtest.net". Things to keep in mind are Kbps is in bits and HTTP data is often compressed so the "downloaded bytes" will be significantly smaller for highly compressible data. Also, don't forget that any old process might be doing any old thing on the internet these days (without stricter firewall settings) ..

I like flindenberg's answer (don't change the accept), and I noticed that some polling periods would return "0" that aligns with his/her conclusions.

Use at your own peril.

void Main()
{
    var nics = System.Net.NetworkInformation.NetworkInterface.GetAllNetworkInterfaces();
    // Select desired NIC
    var nic = nics.Single(n => n.Name == "Local Area Connection");
    var reads = Enumerable.Empty<double>();
    var sw = new Stopwatch();
    var lastBr = nic.GetIPv4Statistics().BytesReceived;
    for (var i = 0; i < 1000; i++) {

        sw.Restart();
        Thread.Sleep(100);
        var elapsed = sw.Elapsed.TotalSeconds;
        var br = nic.GetIPv4Statistics().BytesReceived;

        var local = (br - lastBr) / elapsed;
        lastBr = br;

        // Keep last 20, ~2 seconds
        reads = new [] { local }.Concat(reads).Take(20);

        if (i % 10 == 0) { // ~1 second
            var bSec = reads.Sum() / reads.Count();
            var kbs = (bSec * 8) / 1024; 
            Console.WriteLine("Kb/s ~ " + kbs);
        }
    }
}

Answer 2

Please try this. To check internet connection speed.

 public double CheckInternetSpeed()
 {
        // Create Object Of WebClient
        System.Net.WebClient wc = new System.Net.WebClient();

        //DateTime Variable To Store Download Start Time.
        DateTime dt1 = DateTime.Now;

        //Number Of Bytes Downloaded Are Stored In ‘data’
        byte[] data = wc.DownloadData("http://google.com");

        //DateTime Variable To Store Download End Time.
        DateTime dt2 = DateTime.Now;

        //To Calculate Speed in Kb Divide Value Of data by 1024 And Then by End Time Subtract Start Time To Know Download Per Second.
        return Math.Round((data.Length / 1024) / (dt2 - dt1).TotalSeconds, 2);            
    }

It gives you the speed in Kb/Sec and share the result.

Answer 3

By looking at another answer to a question you posted in NetworkInterface.GetIPv4Statistics().BytesReceived - What does it return? I believe the issue might be that you are using to small intervals. I believe the counter only counts whole packages, and if you for example are downloading a file the packages might get as big as 64 KB (65,535 bytes, IPv4 max package size) which is quite a lot if your maximum download throughput is 60 KB/s and you are measuring 200 ms intervals.

Given that your speed is 60 KB/s I would have set the running time to 10 seconds to get at least 9 packages per average. If you are writing it for all kinds of connections I would recommend you make the solution dynamic, ie if the speed is high you can easily decrease the averaging interval but in the case of slow connections you must increase the averaging interval.

Either do as @pst recommends by having a moving average or simply increase the sleep up to maybe 1 second.

And be sure to divide by the actual time taken rather than the time passed to Thread.Sleep().

Additional thought on intervals

My process would be something like this, measure for 5 second and gather data, ie bytes recieved as well as the number of packets.

var timePerPacket = 5000 / nrOfPackets; // Time per package in ms
var intervalTime = Math.Max(d, Math.Pow(2,(Math.Log10(timePerPacket)))*100);

This will cause the interval to increase slowly from about several tens of ms up to the time per packet. That way we always get at least (on average) one package per interval and we will not go nuts if we are on a 10 Gbps connection. The important part is that the measuring time should not be linear to the amount of data received.