NetworksBy the end of this session, you will:• Define and describe a LAN and WAN.• Understand the hardware required.• Know the 3 LAN topologies.
Networks• What is a Network?• What is a LAN? What hardware do you need tomake one?• What is a WAN? What hardware do you needto make one?• What are the advantages and disadvantagesof a network?• Draw a star, ring and bus network – giveadvantages and disadvantages of each.
NetworksA network is two ormore computers Computer 1connected together sothey can communicatewhich each other. There are 2Computer 2 main types of network…
Networks: LANsLAN LANs are networksstands that are found wherefor: computers within a building need toLOCAL communicate.AREANETWORK They are Small and Local!
Networks: LANs What hardware do you need for a LAN network?•File Server : Runs software, stores files.•Terminals : Workstations that give network access.•Print Server : Queues up all print jobs from users in network.•Cables (wire/optic) : Sends data.
Networks: WANsWAN WANs are networksstands that are found wherefor: computers in different areas orWIDE countries need toAREA communicate.NETWORK They are long range and not local!
Networks: WANsWhat extra hardware do you need for a WANnetwork?•Modems : To connect up to a telephone system (instead of cable).
Networks: Ad/Disad Some advantages of a network are:• Resources (Hardware and Software) can be shared.• Allows more effective communication between users.• Networks are cheaper than “stand-alone PCs.”• Information held on the network can be accessed by allusers with authorised access.
Networks: Ad/Disad Some disadvantages of a network are:• The set-up and maintenance costs can be expensive.• A fault with the network server can cause difficultieswith the organisation.• Networks need security measures to restrict access tousers.• WANs are vulnerable to hackers and viruses.
NetworksAs well as knowing the advantages anddisadvantages of a network…You need to know the advantages anddisadvantages of 3 network topologies…
Network TopologiesThere are 3 main types of networktopologies: The Ring The Bus The Networ Networ Star k k Networ
Network TopologiesThe RingNetwork: Computers are connected together to form a ring shape so that none of them is more important than any of the others.
Network TopologiesThe RingNetwork: Advantages: Disadvantages:•They are cheap to •If there are a lot ofexpand. users on the network, it could slow down as all•The data flows around the data is sent along athe network in one single line.direction so it is fast. •If one computer in the•There is no reliance on ring stops working, thea central computer. whole network stops.
Network TopologiesThe Bus (or line) Network: Computers are connected like bus stops on a main road. None of them is more important than any of the others.
Network TopologiesThe Bus (Line) Network:Advantages: Disadvantages:•It is cheap as it uses •With a lot of users, thethe least amount of network will be slow ascable. data has to travel through the same central•More computers can be cable.added withoutdisruption. •Failure of the central cable will stop the network from working.
Network TopologiesThe Star Network: Computers are connected like a star to a central computer such as a mainframe. This is also called the “host” computer.
Network TopologiesThe Star Network:Advantages: Disadvantages:•If a cable fails, it will •It is more expensive asonly affect one it uses the most cabling.workstation. •Failure of the central•More computers can be computer will stop theadded without network from working.disruption.
Networks: Security Because networks are almost vital to an organisation’s daily activities, they must be kept safe and secure…There are 3 main types of network security…Physical, Access and Data.
Networks: SecurityPhysical security means thatthe hardware of the networkis protected from theft andkept safe.
Networks: SecurityAccess securitymeans that there isa limit to theamount of access auser has to theinformation held onthe network.
Networks: SecurityData security means thatthere are measures taken toprevent the loss of dataheld on the system.