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Networks
What a network is
A network is a connection between 2 or more computer systems so that they are able to share resources, communicate and share files.

Why we network
a. Communication
Networks can range widely to large networks e.g. the internet. This effectively allows any computer connected to the network to communicate with any other computers connected in a similar way. Communication could range from email on PCs to things like Whatsapp or snapchat on a mobile phone.
b. Share Resources
More than one computer connected to a network can share resources for example printers and servers. This means that only one printer is needed for several computers and each can print using it. Sharing a server also means that several computers can access documents saved on the server which can be helpful especially in places like schools where classes need to share documents for information.
c. Share Data
Documents and files can be shared over a network if they are saved to the network rather than a personal document. This can be helpful especially in schools when everyone can reach files saved on the network and save their own copies.


1. Topology - 6 different types - pros & cons
a. Peer to Peer
Peer to peer networking is when two computers are connected and can use the same resources without having to go through a separate server. The problem with this is that if the cable to a pc is cut then that pc is lost from the network. If more than two computers need to be connected another topology would work better.
b. Linear Bus
A linear bus is where all the PCs and resources are joined to the same cable. The pro to this is that several computers are joined and can share data and resources as well as it being easy to add computers to the network, however if the main cable is cut then only the devices on the left of the cut will be connected to each other and the ones on the right will be connected to each other and therefore this could mean that some PCs aren’t connected to the printer and some may not be connected to the server.
c. Star
The star network topology involves around 5 devices connected to a switch. When one device wishes to send to or receive something from another device it is forwarded to the switch along with the ip address of the other device. This makes a switch better than a hub because a hub would send the message to all other devices rather than just the one which it is directed to this then builds up network traffic and makes the computer run slowly. The advantages of a star topology are that it is easy to install and wire, easy to detect faults. On the other hand the star requires more cables than a linear bus and the switch costs extra making it more expensive than a bus.
d. Tree
The tree topology has a ‘backbone cable’ connected to the server which then branches out into several switches connected to PCs like the star. The pros of this setup are that there is point to point wiring for individual PCs and resources and there it is supported by several hardware and software venders. The disadvantages are that there is lots of cabling, if the backbone broke the whole network would crash.
e. Token Ring
Like the bus all devices are connected on the same cable however this time it is connected in the shape of a circle. The advantage of this is that it is easy to add devices however if the ring is cut anywhere the whole network will crash.
f. Wireless
Wireless networks are networks connected over a local range without having to use any cables or wires. The advantage of wireless networking is that adding extra devices is easy however on the other hand security is an issue as anyone who owns a wireless computer can connect to the network.


2. Devices
a. PC
A PC is a personal computer which can be anything from a desktop computer to a laptop.
b. Server
A computer program which manages access to central resources and software
c. Printer
A printer is a device which you can connect to via a network and you can send document to when you want to print it.
d. Hub
A hub is a central server which connects to several PCs and resources. When a PC wishes for something to be sent or received the message goes through the hub and it is forwarded onto all the other machines in the system.
e. Switch
A switch is like a hub in the sense that it connects several PCs however when something needs to be sent or received it only forwards the message to the resource or PC that needs the message not all of the ones in the system.
f. Router
A router connects a small network to a larger network such as the internet.
g. Patch panel
In a network a patch panel connects computers as well as connecting to outside lines.



1. Bandwidth - amount of data, equates hose pipe
Bandwidth is the amount of data that can move between PCs and resources. The bandwidth is the capacity of data transfer available. Fibre optic doesn’t compress the amount of data transferring as much as for example a copper wire therefore meaning that it is a larger bandwidth.
2. Wireless vs Hardwired comparison
• Expense:
Wireless is much cheaper to install than hardwired because when you hardwire a network all the cabling and maintenance costs.
• Security
Hardwired is much more secure than wireless as for wireless all you need is connection however hardwired you have to physically connect your PC therefore making more secure.
• Signal strength
The signal strength in hardwired is much stronger than the signal strength in wireless because you need to have close connection to it whereas hardwired you stay in a strong connection constantly.
• Setup
Wireless connection is very helpful for things such as mobile phones and laptops as you do not need to be attached by cables. Hardwired despite the fact that you need to be attached by cables the cables can also be a health a safety hazard.
2. Peer to Peer vs Client Server comparison
Peer to peer is good for things such as graphic software as they do not need to be shared between PCs therefore all files can be stored on one computer however the problem with this is that if the computer crashes then you cannot access the files stored on this computer. With Client servers you do not have this issue as all files and data can be shared over several connected PCs without it taking a long time – which it would if you sent it over a peer to peer network.




Network Devices
Communication Methods
Network Terms