5 replies to this topic

[Rusko]

Hi everybody!
I'm new in this forum and I've bought my first NETduino plus a few weeks ago (I have a little experience with c# and other uCPU but I'm totally newbie with Arduino/NETduino).
I' writing 2 projects:
1) a server (on NETduino) waiting for a TCP connection and able to manage 2 simple commands: LED ON and LED OFF.
2) a client (on my PC) to establish a TCP connection with the server and able to send the same 2 commands.

This is the code on the server:

public void Listerer()
        {
            bool Loop = true;
            bool RxLoop = true;

            using (Socket socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp))
            {
                socket.Bind(new IPEndPoint(IPAddress.Any, mConfig.Port));

                Debug.Print("Waiting connection...");

                socket.Listen(5);
                while (Loop == true)
                {
                    using (Socket commSocket = socket.Accept())
                    {
                        RxLoop = true;
                        while (RxLoop == true)
                        {
                            if (commSocket.Poll(1, SelectMode.SelectError) == true)
                            {
                                Debug.Print("SOCKET ERROR DETECTED");
                            }

                            if (commSocket.Poll(1, SelectMode.SelectRead) == true)
                            {
                                if (commSocket.Available == 0)
                                {
                                    // Disconnected!
                                    Debug.Print("Disconnected");
                                    RxLoop = false;
                                }
                                else
                                {
                                    int BuffSize = commSocket.Available;
                                    byte[] bytes = new byte[BuffSize];
                                    int count = commSocket.Receive(bytes);

                                    if (count > BuffSize)
                                    {
                                        Debug.Print("ERROR! : Buffer overflow");
                                        PowerState.RebootDevice(false);
                                    }
                                    if (count == 0)
                                    {
                                        Debug.Print("ERROR! : Rx empty string");
                                        continue;
                                    }
                                    string s = new String(Encoding.UTF8.GetChars(bytes));

[here I clean the RX buffer: trim, remove <space>, <newline>, etc etc...]

                                    if (s == "LEDON")
                                    {
[Onboard LED ON]

                                        commSocket.Send(StrToByteArray("OK" + NewLine));
                                    }
                                    else if (s == "LEDOFF")
                                    {
[Onboard LED OFF]

                                        commSocket.Send(StrToByteArray("OK" + NewLine));
                                    }
                                }
                            }
                        }
                    }
                }
            }
        }

and here the code for the client:

        client = new TcpClient(sIPAddress, iPort);
        stream = client.GetStream();

        do {

[TX]        bBuffer = System.Text.Encoding.ASCII.GetBytes("LEDON"); 
            stream.Write(bBuffer, 0, bBuffer.Length);
            stream.Flush();

[RX]        Int32 bytes = stream.Read(bBuffer, 0, bBuffer.Length);

[TX]        bBuffer = System.Text.Encoding.ASCII.GetBytes("LEDOFF"); 
            stream.Write(bBuffer, 0, bBuffer.Length);
            stream.Flush();

[RX]        Int32 bytes = stream.Read(bBuffer, 0, bBuffer.Length);

        } while(1);

I was expecting to see the LED flashing very fast but actually it flashes once per second! Why so slow?

Here what is going on the LAN (thanks Wireshark!):

No.     Time        Source                Destination           Protocol Length Info
      7 0.225345    192.168.1.141         192.168.1.21          TCP      54     57189 > http [ACK] Seq=9 Ack=9 Win=65384 Len=0
      8 0.503487    192.168.1.141         192.168.1.21          HTTP     63     Continuation or non-HTTP traffic
      9 0.515869    192.168.1.21          192.168.1.141         TCP      60     http > 57189 [ACK] Seq=9 Ack=18 Win=1007 Len=0
     10 0.518783    192.168.1.21          192.168.1.141         HTTP     63     Continuation or non-HTTP traffic
     11 0.725376    192.168.1.141         192.168.1.21          TCP      54     57189 > http [ACK] Seq=18 Ack=18 Win=65375Len=0
     12 1.005504    192.168.1.141         192.168.1.21          HTTP     62     Continuation or non-HTTP traffic
     13 1.009187    192.168.1.21          192.168.1.141         TCP      60     http > 57189 [ACK] Seq=18 Ack=26 Win=999 Len=0
     14 1.011983    192.168.1.21          192.168.1.141         HTTP     62     Continuation or non-HTTP traffic

192.168.1.141: PC
192.168.1. 21: NETduino

Replay is very fast but seems each command is split in 2 part and it took about 300ms between the 1st and 2nd part.

I have attached the whole projects (there is a Scan function to search all NETduino boards on the network, maybe someone could be interested in it...).
Please help!

Rusko

Attached Files

•  Projects.zip   22.55KB   32 downloads

[Bill Cook]

I added a timing metric to your code and I'm averaging 10 "LEDON" commands every 400ms, or 1 "LEDON" command every 40ms. It could be something to do with your LAN. Try wrapping areas of the client and server code to figure out where the bottle neck is. I see some places where you could increase performance, but nothing that would have a significant improvement.
Note: I didn't download your entire solution, I just copy/pasted the snippets you provided, so it is possible the performance bottle neck is in another area that I didn't use.
Here is what I'm running on the Netduino:

        public static void Listerer()
        {
            bool Loop = true;
            bool RxLoop = true;

            using (Socket socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp))
            {
                socket.Bind(new IPEndPoint(IPAddress.Any, 1234));

                Debug.Print("Waiting connection...");

                socket.Listen(5);

                int LEDOnCount = 0;
                DateTime referenceTime = DateTime.Now;
                while (Loop == true)
                {
                    using (Socket commSocket = socket.Accept())
                    {
                        RxLoop = true;
                        while (RxLoop == true)
                        {
                            if (commSocket.Poll(1, SelectMode.SelectError) == true)
                            {
                                Debug.Print("SOCKET ERROR DETECTED");
                            }

                            if (commSocket.Poll(1, SelectMode.SelectRead) == true)
                            {
                                if (commSocket.Available == 0)
                                {
                                    // Disconnected!
                                    Debug.Print("Disconnected");
                                    RxLoop = false;
                                }
                                else
                                {
                                    int BuffSize = commSocket.Available;
                                    byte[] bytes = new byte[BuffSize];
                                    int count = commSocket.Receive(bytes);

                                    if (count > BuffSize)
                                    {
                                        Debug.Print("ERROR! : Buffer overflow");
                                        PowerState.RebootDevice(false);
                                    }
                                    if (count == 0)
                                    {
                                        Debug.Print("ERROR! : Rx empty string");
                                        continue;
                                    }
                                    string s = new String(System.Text.Encoding.UTF8.GetChars(bytes));

//[here I clean the RX buffer: trim, remove <space>, <newline>, etc etc...]

                                    if (s == "LEDON")
                                    {
//[Onboard LED ON]

                                        commSocket.Send(StrToByteArray("OK" + "\n"));
                                        led.Write(true);
                                        LEDOnCount++;

                                        if (LEDOnCount == 10)
                                        {
                                            Debug.Print((DateTime.Now - referenceTime).Milliseconds.ToString());
                                            referenceTime = DateTime.Now;
                                            LEDOnCount = 0;
                                        }
                                    }
                                    else if (s == "LEDOFF")
                                    {
                                        commSocket.Send(StrToByteArray("OK" + "\n"));
                                        led.Write(false);
                                    }
                                }
                            }
                        }
                    }
                }
            }
        }
        static OutputPort led = new OutputPort(Pins.ONBOARD_LED, false);
        public static byte[] StrToByteArray(string theString)
        {
            return System.Text.Encoding.UTF8.GetBytes(theString);
        }

[baxter]

I ran your code and the led blinks so rapidly that it appears to be on almost continuously. I use a static IP address, but I notice from MFdeploy that the network configuration was set back to DHCP after running yor code. My Netduino is plugged into a WD Livewire powerline adapter port which is connected to my router. Your router is probably causing your problem.

Output from several connects,

The thread '<No Name>' (0x2) has exited with code 0 (0x0).
Gateway Address: 192.168.0.1
IP Address: 192.168.0.106
Subnet mask 255.255.255.0
Waiting connection...
Disconnected
done
Disconnected
done
Wait Handler OK!
The thread '<No Name>' (0x1) has exited with code 0 (0x0).
Disconnected
done
Disconnected
done

Baxter

[Rusko]

Thank you very much for your answers! I made some tests and the problem seems to be the port I was using. I changed the port (from 80 to 437) and now is very fast (I didn't measure it but I think is similar to the measure Bill Cock made). Now I'm trying to understand why port 80 is so slow. I don't think is the router (I use a WRT54GL with fw Tomato and QoS: port 80 has higher priority than 437...), probably is the lwIP Network stack or some services on my PC... what do you think? Note: I forgot to mention it, I'm using the Firmware 4.2.0 RC1. Thank you again!

[Bill Cook]

There could be a firewall that is causing the delay. See if adding your client app to the exception list helps. Also, see if there are any port 80 exceptions.

[Rusko]

Boh... the firewall seems OK. I will try with a different PC... Thanks again!