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1. LAN WAN and toppologys

   • Networks
     • A network is a collection of computers and equipment connected together
     • A LAN is defined as a collection of computers and peripheral devices connected within a single site
     • A wide area network (WAN) is a network, in which the computers systems are all located relatively distant from each other, for example, in different buildings, all over the country or in different country's
     • A topology is a description/diagram of how computers can be laid out and connected
   • Advantages of networks
     • Communication
       • Using email to communicate with colleagues
       • Using messaging systems to chat while you are working on other things
       • Transferring files between computers
     • Sharing Resources
       • Sharing folders so that you can access files anywhere on the network from any computer and different people can access these files as needed
       • Sharing peripheral devices such as printers and scanners
       • Sharing an internet connection
     • Centralised Management
       • User profiles and security can all be managed centrally
       • Software can be distributed across the network rather than having to install it on each individual computer
       • Users can use any PC on the network but still see their own files.
   • disadvantages of networks
     • Initial cost of servers, communication devices, etc. - expensive
     • Security problems – files sent between computers could spread a virus – not secure
     • Hackers can gain access to data more easily – not secure
     • A network manager may need to be employed – expensive
     • If the server is down, all workstations on the network are affected - unreliable
   • Topologys
     • Bus Network
       • Computers are connected to a single backbone cable. The computers all share this one cable to transmit to each other and only one computer can transmit at a time.
     • Ring Network
       • Computers are connected to adjacent computers in a ring. Computers take turns in transmitting data. This is controlled by a token around the ring. Computers can only transmit when they have the token.
     • star network
       • All of the computers have their own cable that connects them to a central computer. The central computer controls the network.

2. circuit and packet switching

3. network addresses and connecting t9 the internet

4. network protocols

5. wired and wireless connectivity

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