1. Networking Terminology: ISP (Internet service provider) – dialup, dsl, cable LAN (local area network) IP (internet protocol) address, eg. 130.254.204.36 IP addresses mapped to domain names (cs.rit.edu) DNS (domain name server) translates name into IP address IP – low level protocol to deliver packets of data TCP (transmission control protocol) – higher level protocol, establishes a connection and enables to exchange streams of data; data will be delivered in order UDP (User Datagram Protocol) – a low-overhead, connectionless protocol (one application to another)

2. Networking Client/server computing: sockets (logical endpoints of communication in Java) similar to read/write to a file socket attached to a port (a number 0…65536 – e.g. 25 for e-mail, 80 for the web server) Server socket: ServerSocket ss = new ServerSocket(port); (might throw a BindException ) Socket socket = ss.accept(); (waits for client to connect)

3. Networking Server socket: ServerSocket ss = new ServerSocket(port); (might throw a BindException ) Socket socket = ss.accept(); (waits for client to connect) Client socket: Socket s = new Socket(serverName, port); e.g., Socket s = new Socket(“130.254.204.36”, 8000); Then work similarly to files.

4. Networking Data transmission: Server: Client: int port = 8000; DataInputStream in; DataOutputStream out; ServerSocket server; Socket socket; server = new ServerSocket(port); socket = server.accept(); in = new DataInputStream( socket.getInputStream()); out = new DataOutputStream( socket.getOutputStream()); System.out.println( in.readDouble()); out.writeDouble(aNumber); int port = 8000; String host = “localhost”; DataInputStream in; DataOutputStream out; Socket socket; socket = new Socket(host, port); in = new DataInputStream( socket.getInputStream()); out = new DataOutputStream( socket.getOutputStream()); out.writeDouble(aNumber); System.out.println( in.readDouble());