diff --git a/server.java b/server.java
new file mode 100644
index 0000000..5fd6bd9
--- /dev/null
+++ b/server.java
@@ -0,0 +1,90 @@
+package TCP;
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.io.OutputStreamWriter;
+import java.net.ServerSocket;
+import java.net.Socket;
+import java.util.Random;
+import java.awt.*;
+
+import TCP.MySegment;
+
+public class Server {
+	public static int port=8888;
+	public static void send(String content,OutputStreamWriter osw) throws IOException, InterruptedException
+	{
+		Random random=new Random();
+		if(random.nextInt(100)>30)
+		{
+			osw.write(content+"\n");
+			osw.flush();
+			Thread.sleep(200);
+		}
+		else
+		{
+			content="00"+content.substring(2);
+			osw.write(content+"\n");
+			osw.flush();
+			Thread.sleep(200);
+		}
+	}
+	public static void main(String []args) throws IOException, InterruptedException
+	{
+		int ackno=0;
+		int window=1;
+		StringBuilder content =new StringBuilder("0");
+		boolean ack=false;
+		int acked=-1;
+		for(int i=1;i<50;i++) content.append((char)('0'+i%10));
+		
+		Frame frame =new Frame("Server");
+		frame.setLayout(new GridLayout(2,1));
+		frame.setTitle("Server");
+		frame.setSize(500, 100);
+		frame.setLocation(800, 200);
+		frame.setAlwaysOnTop(true);
+        frame.setVisible(true);
+        Label toSend=new Label("toSend:  "+content.toString());
+        frame.add(toSend);
+        
+		ServerSocket server=new ServerSocket(port);
+		Socket socket=server.accept();
+		OutputStreamWriter osw=new OutputStreamWriter(socket.getOutputStream());
+		BufferedReader br=new BufferedReader(new InputStreamReader(socket.getInputStream()));
+		while(true)
+		{
+			String[] segkey=null;
+			for(int i=0;i<50;i++)
+			{
+				if(i>acked&&i<=window+acked)
+				{
+					MySegment seg=new MySegment(socket.getLocalPort(),socket.getPort(),i,ackno,ack,window,(byte)(i%10));
+					send(seg.toSend,osw);
+					System.out.println("sent segment "+seg.SequenceNumber);
+					segkey=br.readLine().split("--");
+					MySegment segACK=new MySegment(Integer.parseInt(segkey[0]),Integer.parseInt(segkey[1]),Integer.parseInt(segkey[2]),Integer.parseInt(segkey[3]),Boolean.parseBoolean(segkey[4]),Integer.parseInt(segkey[5]),Byte.parseByte(segkey[6]));
+					if(segACK.Check==Integer.parseInt(segkey[7]))
+					{
+						if(segACK.ACK)
+						{
+							acked=segACK.AcknowledgementNumber>acked?segACK.AcknowledgementNumber:acked;
+							window=segACK.Window;
+							System.out.println("received ACK of "+segACK.AcknowledgementNumber);
+							
+						}
+					}
+				}
+			}
+			toSend.setText("toSend:  "+content.substring(acked+1).toString());
+			if(acked==49)
+			{
+				toSend.setText("All data sent to Client successfully!");
+				Thread.sleep(3000);
+				break;
+			}
+		}
+		socket.close();
+		server.close();
+	}
+}