Networks

1. Networks Am I hooked up?

2. Networks • Definition • Sizes of networks • Types • Advantages and disadvantages • How data is sent • Transmission media • Business uses

3. 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 or phone line

4. 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.

5. Sizes of networks

6. Types of networks • Peer-to-peer • Client/server

7. 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.

8. 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.

9. Advantages of a network A network allows users to: • communicate • share resources • exchange information • store data

10. 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.

11. Share resources A network allows users to share resources such as: • printer • application software

12. Exchange information Users on a network can share files and information.

13. 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.

14. 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.

15. 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

16. Types of transmission media The transmission of data is done using: • phone lines • television cable • wireless links such as satellite.

17. 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.