Networks

Networks

1. Types of Topologies

   • Ring Topology
     • Peer-to-peer network as there is no server
     • All the Computers are arranged in a circle
     • Data sent by one computer passes around the ring until it reaches the correct computer
     • Advantages
       • Network not dependent on central computer
       • Each computer has the same access as the others so no one computer can 'hog' the network.
     • Disadvantages
       • Faults are difficult to locate
       • If there is a break in the connection (wire/wireless), then the whole network fails.
       • Its impossible to keep the network running whilst equipment is added or removed because there is only one path for the data to flow.
   • Bus Topology
     • All devices connected tot he network are connected to a common shared cable called the backbone.
     • Signals are passed in either direction along the backbone
     • Advantages
       • Cost effective because pf the small amount of cable needed
       • Simple cable runs makes it easy to install
       • Easy to add extra devices to the network
     • Disadvantages
       • If more than about 12 devices are connectd to the network, then the performance of the network is degraded.
       • If there is a break in the backone cable, then the network cannot be used
   • Star Topology
     • Uses a central connection point to connect all the devices on the network together
     • Central connection point can be a hub/switch/router
     • Advantages
       • Fault tolerant
         • If one of the cables fails, then the other computers can still be used
       • Load tolerant
       • Easy to add extra computers
     • Disadvantages
       • Higher cost - The larger the amount of cabling needed makes it more expensive topology.
       • Dependent on the central hub, router or switch - If the device at the centre of the network fails, then the whole network will fail.

2. Wireless Networks

   • Lots of computers are now able to connect to the internet to other devices wirelessly.
   • The data transfer medium thought the air through which radio waves travel.
   • Wireless networks allow people to connect to the internet wirelessly.
     • Means that they can work anywhere that they can get a radio signal
   • Places where you can access the internet using Wi-Fi is called a Hotspot
   • To set up a Wi-Fi Network you will need:
     • Broadband connection to the internet
     • A Router
     • Wi-Fi enabled computers (Most computers have a wireless adapter installed in them)
   • Advantages
     • Allows inexpensive LANS to be set up without cables
     • Allows people the freedom of working anywhere a signal can be received
     • Ideal for networks in old listed buildings where cables would not be allowed to be installed
     • Global set of standards - You can use Wi-Fi all over the world
   • Disadvantages
     • Power cpmsumptions is high - Which means laptops soon exhust thier recharge bateriers
     • May be health problems in using Wi-FI
     • Security problems even when encryption is used.
     • Home networks have a very limited range
     • Can get interference if wireless netwrk signals start to overlap.

3. How Wi-Fi Works

   • 1. Router is connected to the internet by a high-speed broadband connection.
   • 2. The router recieves data from the internet.
   • 3. Transmits the data as a radio signal using an antenna
   • 4. The computers wireless adapter picks up the signal and turns the radio signals to data that the computer can understand.

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