3.4.1+LAN,+WAN,+Client,+Server

=**__LAN (Local Area network)__**=
 * Covers a small physical area, such as a school, building or office
 * Typically there is a central server that stores the shared data and software
 * The computers and peripherals are directly linked to one another via cable or microwaves
 * Advantages & disadvantages:
 * + It is easily possible to share data, printers and other peripherals
 * + One can load the same data from the server onto every computer, so one can log in into the same user account on every computer
 * + Compared to the transfer rates of WAN it is relatively fast. At the moment the typical maximum speed of a LAN is 1Gbit/s
 * - It only covers a comparably small physical area
 * LANs are usually set up in a client/server mode of operation. There is a central server and one has to log in on a client computer first, to gain access to the network.
 * Many LANs are connected to other WANs (such as the Internet)
 * To connect to other LANs or WANs usually a **gateway** is used, enabling access to services available in other networks and the Internet, for instance

=**__WAN (Wide Area Network)__**=
 * Covers a large physical area, even intercontinental sometimes
 * Different communication medias and computer facilities are often used in one WAN
 * A WAN is more 'public' than a LAN; users from often times very different localities can access the network
 * A WAN is often used by companies, which are located in several places around the globe and need a network connection between those places
 * The best-known example of a WAN is the Internet
 * Advantages & disadvantages:
 * + It can cover a very large physical area
 * + Very many different servers and clients can connect with another
 * - It is slower in transfer rates than LAN. Currently the maximum transfer rate that is available for the common user is 100Mbit/s with VDSL

=**__Server__**= A server is a computer or other device linked to a LAN or WAN that provides services to the clients in the network.The term 'server' refers to the soft- and hardware. Examples:
 * Email server: a computer, which provides email functionality, so that clients can send and receive emails
 * Web server: a server, which hosts some sort of web site, which can be accessed by clients
 * File server: a server, which stores data and files and which can be accessed by clients
 * DHCP (Dynamic Host Configuration Protocol) server: a server, which assigns IP addresses to the clients, to enable them to access the network and to make it possible to access them in the network

=**__Client__**= A client is a piece of software, which requests actions from a server and uses the services provided by a server. It makes the services provided by the server available to the user. Examples:
 * Email clients: allow the user to access and manage their emails. Without a server though, these emails could not be sent or received

For some further information on client/server networks, click here: http://compnetworking.about.com/od/basicnetworkingfaqs/a/client-server.htm

Created by Jocbe Last update: 22. November 2010

Sources:
 * Jones, Richard. Computer Science Java Enabled. Victoria: IBID Press, 2004.