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.