CPSC 3600 - DAY 3
JANUARY 18, 2017

================================================================================

INTRODUCTION TO NETWORK PROGRAMMING
-----------------------------------

	.Network programming and socket programming are used interchangeably.

	.Client and Server.
		.Client program initiates communication.
		.Server program waits passively for and then responds to client
		that contacts it.
		.Both client and server computers can run multiple applications
		at the same time, e.x. browser, IM, etc.
		.Server starts first, client starts second.
		.Communicates through sockets.

	.Server Identification.
		.to identify a server, it needs to know the IP address
		and the port number.

	.The client-server distinction is important because the client needs
	to know the server's address and port initially.

	.The server can learn the client's address information when it recieves
	the initial communication from the client.

	.Concurrent Servers
		.A server can handle more than one client at a time.
		.It uses more than one thread.
		.A client does not have to wait for a previous client to finish
		.For example, one client is downloading a movie, while the
		second client requests a short download (song).

	.Socket
		.A socket is an abstraction through which an application may
		send a recieve data.
		.A socket allows an application to plug in to the network and 
		communicate with other applications that are plugged in to the 
		same network
		.Information written to the socket by an application on one 
		machine can be read by an application on a different machine.
	
	.TCP vs. UDP
		.Transmission Control Protocol (TCP): reliable, connection
		oriented.
		.User Datagram Protocol (UDP): unreliable, connectionless
		.The TCP and UDP protocols are two different commmunication
		protocols that handle data communications between terminals
		in an IP network (the Internet)