Networks Grade 10 Vera Castleman The Network System

Networks Grade 10 © Vera Castleman

The Network System l l A network links components electronically. Each component is a NODE. A node could be: l l A PC A printer A modem etc. The essential components of a network are l l Network devices (e. g. computers, printers) Communication channels (e. g. cables) Network interface cards Network software.

Types of Networks l Networks can be: l l Simple two computers at home could be linked directly. If both have the same control called a peer-to-peer network. Complex server based the server controls the components linked together in the network.

Advantages of a network l l l l Share Resources Centralise and update data in one place Centralise programs on server Upgrades can be done in one place Files transfer is easy. Contact maintained by using e-mail which can also update Inter-Office appointments. Security is maintained sensitive material is restricted from general use. Networks save time and resources. They improve productivity and also save money.

Disadvantages of a network l l are always a concern in a network. A well managed network will restrict unauthorised users Each user will have a profile protected by a password. Rules for creating a password l Don’t use things that a user can guess like a pet’s name, a boy or girl friend’s name, your birth date etc. l Change your password regularly especially if you think it has been guessed. l Never use a sequence of letters or numbers (e. g. 12345 or abcde) l Use an alphanumeric code l Make some of the letters uppercase l Substitute numbers for some of the letters Sabelo 8 Ab 310 l DO NOT write it down!

Black, Grey and White Hats l l l Black Hats gain access to try to steal or destroy information They will leave a message so that people will know that they have been in. Grey Hats ½ a White and ½ a Black Hat. They enjoy the challenge of breaking in – will usually inform the company and suggest payment for providing a fix for the security breach. White Hats will do it for a challenge and will let the company know how to fix it.

Examples of networks l l l PAN (Personal Area Network) e. g. pictures taken with your cell phone can be sent to your printer. HAN (Home Area Network) 2 or more PC’s in a home are connected to share resources, OAN (Office Area Network) a small office connecting as above LAN (Local Area Network) exists in a company within a small geographical space e. g. one office complex. WAN (Wide Area Networks) cover a vast geographical span e. g. between offices and the head office, various colleges of a university etc. GAN (Global Area Networks) refers to the internet or a company with ties to a company in another country usually via satellite.

Communication Channels l l l l Telephone lines Coaxial Cables UTP cabling Microwave Transmission Fibre Optic cables Infrared Transmission Cellular Radio Systems

Communications Interfaces l An interface is a piece of hardware that helps various devices to communicate. There are many ways that different communication components can be linked: l l l Modem Switch Router