Networks

Networks

1. What is a network?

   • A network is a group of two or more computer systems linked together

2. Advantages of a Network

   • Devices such as printers and scanners can be shared
   • The internet and files can be shared more easily
   • Users can send messages to others using e-mail
   • Files can be saved and backed up centrally
   • Flexible access – files can be accessed by a user from any of the computers as they are not stored on a particular one
   • Software can be distributed across the network rather than having to install it on each individual computer

3. Disadvantages of a Network

   • Cabling and infrastructure is expensive
   • A security breach could give access to the whole network

4. Networking Hardware

   • Hub
     • Are hardware devices that connect many network devices together making the into a single network segment. They have a number of input and output ports which connect to each other.
       • When data from one computer is transmitted to all computers on the network, leading to unnecessary network traffic.
   • Switch
     • Is very similar to a hub but directs network traffic only to the intended recipient, thus cuts down on unnecessary network traffic. It does this by building up a table of addresses of computers on the network.
       • Can be a security risk unless properly secured using encryption, hiding the network identify or by only allowing access to certain MAC addresses. It does this by building up a table of addresses of computers on the network.
   • Router
     • Often large ones are used on the Internet, whereas small ones are used within the home to connect individual computers to an Internet Service Provider. It can be either wireless or cabled. Formats the data into a form required by the protocols (rules) of the network.
       • Used to forward data packets between different computer networks. The router reads the final destination address of the packet and then sends it to a router that is closer to the destination.
   • Network Interface Card
     • The card that goes into a computer to provide a connection to a network. It has a unique address called a MAC address. In most new computers it is built into the motherboard.
   • Wireless Access Point
     • Allows wireless devices to connect to a wired network. Converts data it receives through cables into a wireless signal and vice versa.

5. P2P

   • In a Peer-to-peer network, each computer stores files and can act as a server. Each computer has an equal responsibility to provide data to other computers.

6. Client-Server

   • This is the relationship between 2 computers in which the client makes a request from the server. The client is dependent on the server to manage all of the information.