Socket Programming in Java- For Simplex Communication using Connectionless Service

Program in Java to execute a simple connectionless communication between a server and client.

There are two types of protocol in the transport layer for communication:

1) TCP

2) UDP

In UDP (User Datagram Protocol), a connection is not formed online in TCP where the client sends a request to the server for a connection. The message is sent in the form of a datagram packet. Datagrams upon arrival contain the address of the sender which the server uses to send data to the correct client.

The algorithm for the whole process is:

SERVER:

1) Create a UDP socket-

serverSocket=new DatagramSocket();

2) Read request-

serverSocket.receive(requestPacket);

3) Write reply-

serverSocket.sent(reply packet, host, port);

4) Continue to read request.

CLIENT:

1) Create Datagram Socket for client-

clientSocket=new DatagramSocket();

2) Send request-

clientSocket.send(requestPacket,host,port);

3) Read reply-

clientSocket.receive(reply Packet);

4) Close-

clientSocket.close();

UDP advantages and disadvantages:

1) It is faster than TCP

2) Not reliable is a connection is not formed

3) No acknowledgment when the message is received.

Classes used:

1) DatagramPacket

2) DatagramSocket

Methods used:

1) receive()

2) send()

3) close()

DatagramPacket Objects:

1) DatagramPacket(byte[] buff, int length)

2) DatagramPacket(byte[] buff, int length, InetAddress address, int port)

## byte format is used to send or receive.

Inet Address:

Java representation of address-

1) InetAddress address = InetAddressgetByName("nameofthesite.com");

2) InetAddress address = InetAddress.getLocalHost();

Simplex Communication is one-way communication. It means that messages can be sent from one side and received from the other.