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I'm trying to send data using the booster pack cc3000 by Texas Instruments. Therefore I implemented a TCP server socket on my board. I can successfully accept a pending connection and send and receive data on the given socket. In my protocol the client is responsible for closing the connection after reading the response. But after some transmissions the transmissions becomes slow. If I inspect the WLAN traffic using Wireshark I see there is a problem with the socket close procedure. My client is a java based program. The board uses address 100 and the computer runs under 102.

The TCP stream looks the following: 

 31 4.696711000    192.168.2.102         192.168.2.100         TCP      66     50721 > http-alt [SYN] Seq=0 Win=8192 Len=0 MSS=1460 WS=4 SACK_PERM=1
 32 4.700359000    192.168.2.100         192.168.2.102         TCP      58     http-alt > 50721 [SYN, ACK] Seq=0 Ack=1 Win=1460 Len=0 MSS=1460
 33 4.700394000    192.168.2.102         192.168.2.100         TCP      54     50721 > http-alt [ACK] Seq=1 Ack=1 Win=17520 Len=0
 34 4.700461000    192.168.2.102         192.168.2.100         HTTP     55     Continuation or non-HTTP traffic
 35 4.705454000    192.168.2.100         192.168.2.102         TCP      54     http-alt > 50721 [ACK] Seq=1 Ack=2 Win=1460 Len=0
 36 4.705476000    192.168.2.102         192.168.2.100         TCP      57     [TCP segment of a reassembled PDU]
 37 4.709035000    192.168.2.100         192.168.2.102         TCP      54     http-alt > 50721 [ACK] Seq=1 Ack=5 Win=1460 Len=0
 38 5.194961000    192.168.2.100         192.168.2.102         TCP      58     [TCP segment of a reassembled PDU]
 39 5.196220000    192.168.2.100         192.168.2.102         HTTP     154    Continuation or non-HTTP traffic
 40 5.196244000    192.168.2.102         192.168.2.100         TCP      54     50721 > http-alt [ACK] Seq=5 Ack=105 Win=17416 Len=0
 41 5.196286000    192.168.2.102         192.168.2.100         TCP      54     50721 > http-alt [FIN, ACK] Seq=5 Ack=105 Win=17416 Len=0
 42 5.202194000    192.168.2.100         192.168.2.102         TCP      54     http-alt > 50721 [ACK] Seq=105 Ack=6 Win=1460 Len=0
138 24.245036000   192.168.2.100         192.168.2.102         TCP      54     http-alt > 50721 [FIN, ACK] Seq=105 Ack=6 Win=1460 Len=0
139 24.245060000   192.168.2.102         192.168.2.100         TCP      54     50721 > http-alt [ACK] Seq=6 Ack=106 Win=17416 Len=0

After about 10 transmissions I get a FIN/ACK cascade. The last FIN/ACK above is part of this cascade. It looks like if the sockets are not completely closed and the HW module starts now closing all sockets in a row. 

    My Java - client does the following
    Socket b = new Socket("192.168.2.100",8080);
    OutputStream o = b.getOutputStream();
    o.write(10);
    o.write(0);
    o.write(0);
    o.write(0);
    o.flush();

    InputStream i = b.getInputStream();

    int id = i.read();
    int gId = i.read();

    int lengthA = i.read();
    int lengthB = i.read();
    int length = (lengthB<<8)|lengthA;
    if(length < 0|| length > 1000)
    {
        b.close();
        return;
    }

    System.out.println(new Date()+" GantryID: "+gId+" Package with id: "+id+" has length: "+length+" payload: ");

    DataInputStream ds = new DataInputStream(i);
    byte[] buffer = new byte[length];
    ds.readFully(buffer);       
    b.close();
    System.out.println(new String(buffer));

The server is a little more complex but the important commands are:

return recv(handle, data, size, 0); //Read request header
return recv(handle, data, size, 0); //Read request payload
send(handle, data, size, 0); //Write response header
send(handle, data, size, 0); //Write response payload
//No Close only set socket handle to -1

Does anyone have a idea what is going on. I would appreciate any help and ideas.

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