1. Introduction to Sockets “A socket is one endpoint of a two-way communication link between two programs running on the network. A socket is bound to a port number so that the TCP layer can identify the application to which data is destined to be sent.”

3. Networking Review TCP/IP Protocol Suite Application programming interface to TCP/IP (API) BSD Unix Java.net.Socket Platform Independence

5. Ports TCP and UDP use ports to map incoming data to a particular process running on the computer Ports are 16 bit numbers Need IP Address (32-bits) and port. 0-1023 Restricted out of 65,535.

6. Networking Classes in Java TCP: URL, URLConnection, Socket, ServerSocket UDP: DatagramPacket, DatagramSocket, MulticastSocket Socket and ServerSocket form two ends of communicaiton link.

8. Procedure Open a socket Open an input and output stream to the socket Read from and write to the stream according to the server’s protocol close streams close socket