Computer Networks

Peer-to-Peer Network

• https://www.youtube.com/watch?v=aFU3ug9_BJQ (Einbetten)
• Peer-to-Peer is a network arrangement where each computer is of an equal status.
• Benefits:
• - Saves on cost as no server is needed
• - No need to hire a network manager, users have the responsibility
• - Easy to set up
• - No reliance on a server
• - Lower operating costs
• - Users can decide what resources other users can use on their computer
• Drawbacks:
• - Backups cannot be made centrally
• - Users need more IT knowledge
• - Less efficient security
• - Some computers may run slowly
• - Users may find it difficult to find files as they are not held centrally
• - Only suitable for small networks, around 15 networked computers
• Bildunterschrift: Peer to Peer video

Client-server Networks

• https://www.youtube.com/watch?v=mm3r8EG4wLQ (Einbetten)
• Benefits:
• - Security is more efficient because it is centralised
• - The data is stored centrally, all users have access to the same set of data
• - Faster access to programs and files because servers are used, they are powerful computers
• - All the administration of the network, such as username and passwords, is performed centrally. This is so that users do not have to worry about that.
• Disadvantages:
• - Servers are expensive
• - Need to be an expert on networked systems
• - If the server breaks down it renders the network unusable until it can be repaired.
• Bildunterschrift: Client-server networks video

Peer to Peer network

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• Bildunterschrift: In a Peer to Peer network all the computers are of equal status

Client-server network

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• Bildunterschrift: With Client-server networks a more powerful computer is in charge of the networking facilities

Ring Topology

• https://www.youtube.com/watch?v=OSnnJNTa5cU (Einbetten)
• Bildunterschrift: Ring Topology Network video
• Ring network's are also peer-to-peer networks because there is no server.
• About the Ring Topology:
• - All the computers are arranged in a circle
• - Data sent by one computer passes around the ring until it reaches the correct computer
• Advantages:
• - Does not depend on a central computer
• - Each computer has the same access, so no computer can traffic the network.
• Disadvantages:
• - If there is a break in the connection, whether wires or wireless, the whole network will fail.
• - Faults are difficult to locate
• - The network cannot be kept running whilst new equipment is being added or removed as there is only one path the data can follow.

Bus Topology

• https://www.youtube.com/watch?v=Awt4ikvFYyI (Einbetten)
• Bildunterschrift: Bus Topology Network video
• About Bus Topology:
• All the devices are connected to the network by a common shared cable called the backbone. Signals are passed in either direction along the backbone.
• Advantages:
• - Cost effective, small amount of cable needed
• - Simple cables make it easy to install
• - Easy to add extra devices to the network
• Disadvantages:
• - If more than 12 devices are connected to the network it degrades the performance of the network.
• - If there is a break in the backbone cable then the network is unable to be used.

Star Topology

• https://www.youtube.com/watch?v=EQ3rW22-Py0 (Einbetten)
• Bildunterschrift: Star Topology Network video
• About Star Topology:
• It uses a central connection point to connect all the devices on the network together. The central connection point can be a hub, a switch or a router.
• Advantages:
• - If one of the cables fails, other computers can still be used
• - Extra computers can be added without much affect to performance, this is because the computers have their own path to the server.
• - It is easy to add extra computers without disturbing the network
• Disadvantages:
• - Higher cost as there is a large amount of cabling
• - Depend on central router, so if the router fails then the whole network will fail.

Bus Topology Diagram

Ring Topology Diagram

Star Topology Diagram

Wireless Networks

• https://www.youtube.com/watch?v=okeSqr5eOmU (Einbetten)
• About Wireless Networking:
• Majority of computers are now able to connect to the Internet or communicate with other computers in a LAN wirelessly. Wireless connection allows data to be transferred through the medium that is the air, where radio waves travel.
• Wireless networks allow people to connect to the Internet or to a LAN wirelessly. This enables them to work anywhere where they can get a radio signal for their network.
• Many people, especially people who travel a lot, will need to access the Internet on a regular basis. There are many public places available where the Internet can be accessed wirelessly using a laptop of computer, or any other portable devices such as a mobile phone.
• Places where you can access the Internet using Wi-Fi are called HOTSPOTS.

Advantages & Disadvantages

• - It allows inexpensive LANS to be set up without the need for cables
• - Gives people the freedom of working anywhere a signal can be received
• - It is ideal for networks in older buildings where cables would not have been installed
• - You can use it all over the world.
• - Power consumption is high, laptops soon exhaust their rechargeable batteries
• - Might be health problems involved with using Wi-Fi
• - Chance of security problems, whether encryption has been used or not
• - Home networks have a very limited range for devices that want to connect, such as 150 ft and cannot hold more than say 20 devices. A school would have to have more than one access point.
• - There can be interference if wireless network signals start to overlap.

How Wi-Fi works