Easy Steps to implement UDP Server and Client Sockets
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This document discusses UDP sockets and provides code examples for UDP client-server communication. UDP sockets are connectionless and unreliable compared to TCP sockets but provide faster transmission of data. The server creates a DatagramSocket and receives DatagramPacket objects without maintaining individual connections to clients. Clients also use DatagramSockets to send and receive DatagramPacket objects from the server. The code examples show the steps to create and use DatagramSockets on both the server and client sides.
![UDP Server
• Process involves the following nine steps
1. Create a DatagramSocket object
DatagramSocket datagramSocket =
new DatagramSocket(1234);
2.Create a buffer for incoming datagrams
byte[] buffer = new byte[256];](https://image.slidesharecdn.com/udp-140411135143-phpapp01/85/Easy-Steps-to-implement-UDP-Server-and-Client-Sockets-4-320.jpg)
![UDP Client (contd)
3. Send the datagram message
datagramSocket.send(outPacket);
4. Create a buffer for incoming datagrams
byte[] buffer = new byte[256];
5.Create a DatagramPacket object for the
incoming datagrams
DatagramPacket inPacket =
new DatagramPacket(buffer, buffer.length);](https://image.slidesharecdn.com/udp-140411135143-phpapp01/85/Easy-Steps-to-implement-UDP-Server-and-Client-Sockets-10-320.jpg)
Easy Steps to implement UDP Server and Client Sockets
- 2. Datagram (UDP) Sockets • Unlike TCP/IP sockets, datagram sockets are connectionless • Connection between client and server is not maintained throughout the duration of the dialogue • Each datagram packet is sent as an isolated transmission • Datagram (UDP) sockets provide a faster means of transmitting data than TCP/IP sockets, but they are unreliable.
- 3. Datagram (UDP) Sockets (contd) • The server does not create an individual Socket object for each client • Instead of a ServerSocket object, the server creates a DatagramSocket object • As does each client when it wants to send datagram(s) to the server • DatagramPacket objects are created and sent at both ends, rather than simple Strings.
- 4. UDP Server • Process involves the following nine steps 1. Create a DatagramSocket object DatagramSocket datagramSocket = new DatagramSocket(1234); 2.Create a buffer for incoming datagrams byte[] buffer = new byte[256];
- 5. UDP Server (Contd) 3. Create a DatagramPacket object for the incoming datagram • The constructor for this object requires two arguments: • the previously-created byte array • the size of this array DatagramPacket inPacket = new DatagramPacket(buffer, buffer.length);
- 6. UDP Server (Contd) 4. Accept an incoming datagram datagramSocket.receive(inPacket); 5. Retrieve the sender's address and port from the packet InetAddress clientAddress = inPacket.getAddress(); int clientPort = inPacket.getPort();
- 7. UDP Server (contd) 6. Retrieve the data from the buffer String message = new String(inPacket.getData(), 0,inPacket.getLength()); 7. Create the response datagram – Create a DatagramPacket object, using an overloaded form of the constructor thattakes four arguments: • the byte array containing the response message; • the size of the response; • the client's address; • the client's port number.
- 8. UDP Server (contd) DatagramPacket outPacket = new DatagramPacket(response.getBytes(), response.length(),clientAddress, clientPort); 8.Send the response datagram datagramSocket.send(outPacket); 9.Close the DatagramSocket datagramSocket.close();
- 9. UDP Client • Setting up the corresponding client requires the eight steps listed below 1. Create a DatagramSocket object DatagramSocket datagramSocket = new DatagramSocket(); 2. Create the outgoing datagram • This step is exactly as for step 7 of the server program DatagramPacket outPacket = new DatagramPacket(message.getBytes(), message.length(), host, PORT);
- 10. UDP Client (contd) 3. Send the datagram message datagramSocket.send(outPacket); 4. Create a buffer for incoming datagrams byte[] buffer = new byte[256]; 5.Create a DatagramPacket object for the incoming datagrams DatagramPacket inPacket = new DatagramPacket(buffer, buffer.length);
- 11. UDP Client (contd) 6. Accept an incoming datagram datagramSocket.receive(inPacket); 6. Retrieve the data from the buffer String message = new String(inPacket.getData(), 0,inPacket.getLength()); 8. Close the DatagramSocket datagramSocket.close();