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Networks Am I hooked up? Networks • • • • • • • definition sizes of networks types advantages and disadvantages how data is sent transmission media business uses What is a network? A network is a group of 2 or more computers that are linked together either by wires or by a wireless means. In order to network computers you require: network hardware such as a network interface card network software connecting devices such as hubs, routers, etc. communication lines such as cable, wireless capacity or phone line Sizes of networks • A local area network is a network that connects a few computers in a building or in close proximity. A school network is an example of a LAN. • A wide area network (WAN) is a network that connects 2 or more LANs. WANs often span across a large area such as a country, a continent or even the world. The Internet is an example of a WAN. LAN Topologies • Topology simply means the physical arrangement of the LAN • Bus topology – daisy chain of devices • Star topology – A hub connected to nods • Ring topology – All connected in a circle • Tree topology – Combination of a star and bus Sizes of networks Types of networks • Peer-to-peer • Client/server Peer-to-peer networks Peer-to-peer networks have no dedicated server but rather the individual computers act as servers and can share files. Users generally have read access but not write access. A peer-to-peer network you may be familiar with is Napster. It is a global peer-to-peer network for the purpose of sharing music files. Client/server networks In a client/server network, a server (or central computer) has a large disk for storage. Computers connected to the server share processing and storage functions with the server. A client (or user PC) can access files on the server but not necessarily other user files. A client/server network generally requires a login to access the network. Advantages of a network A network allows users to: • communicate • share resources • exchange information • store data Communication • A network allows users to communicate via electronic mail (email) and to send files as attachments. • Users in a network may also teleconference or video conference. Share resources A network allows users to share resources such as: printer application software Exchange information Users on a network can share files and information. Storage of data • Files stored on a network can be backed up automatically. • Network storage of files creates great storage capacity and the ability to access files from remote locations. How data is sent • Data is transmitted in small pieces called packets. The network uses a protocol or set of rules that determines how packets are configured and transmitted. An example of a network protocol is Transmission Control Protocol/Internet Protocol (TCP/IP). • Every computer requires an IP address which is either permanently assigned or dynamically assigned at startup. Disadvantages • the cost to setup a network • the administration costs to maintain and manage the network • viruses can spread quickly across a network • loss of privacy Types of transmission media • The transmission of data is done using phone lines, television cable or wireless links such as satellite. Business uses • Networks used in business are often client/server networks where users login in to access the server. The server is run by an administrator who ensures that backups are done on a regular basis. • Business may also use intranets or private web sites not accessible to the public in order to make information and files available online. Footnotes Woman. Hassle Free Clip Art. Viewed March 3, 2006. <http://www.hasslefreeclipart.com/clipart_compusers/page1.html> Little_baldguy. Hassle Free Clip Art. Viewed March 3, 2006. <http://www.hasslefreeclipart.com/clipart_compusers/page1.html> Nerd. Hassle Free Clip Art. Viewed March 3, 2006. <http://www.hasslefreeclipart.com/clipart_compusers/page1.html> Stressed_out. Hassle Free Clip Art. Viewed March 3, 2006. <http://www.hasslefreeclipart.com/clipart_compusers/page1.html> Buculei, Nicu. Open Clip Art. Viewed March 3, 2006. < http://www.openclipart.org/cgi-bin/navigate/computer/hardware> Fitzsimon, Andy. Computer. Open Clip Art. Viewed March 3, 2006. <http://www.openclipart.org/cgi-bin/navigate/computer/hardware?page=2> Networks Close this window to return to the course