Computer Communications and Networking

Computer Communications and Networking

1. Why network computers?

   • Sharing resources like internet connections and printers.
   • Easier to manage multiple computers. This includes installing softwares and setting accross multiple computers remotely
   • Users no longer need to be tied t oa single computer to access their data and programs

2. ubiquitous computing : that surrounds us and is everyone in our lives

3. Network Topology

   • mathematical study of shapes and nodes
   • The structure of the under-laying nodes and connections for a network is known as topology
   • LAN: local area network,only specific people can access it
     • e.g: schools use LANS
   • WAN: Wide area network, only one person can access it
   • TYPES OF TOPOLOGY
     • Bus network
       • Has a central cable that all devices are connected to
       • Only once device at a time can access the bus at a time
       • Terminators are placed at each end of the bus network
       • IF a device wishes to communitcate on the network, it first chekcs to see if there are any traffic on the network
       • Easy to add nodes to it.
       • Heavily dependant on the main cable, if it goes down then all of the devices will go down as well.
       • Quite slow
     • Ring Network
       • No central host computer, none of the nodes have overall access to the network
       • The messages in the network flow from node to node
       • An imaginary token is continuiously passed around the ring, token is a small packet of data that contains a bit of data
       • As long as one device has the token no other device can send data
       • Much faster than the bus network
       • High transmission speeds are possible
       • However cabaling costs are high
       • Hard to extend the ring
     • Star network
       • Most common topology
       • Each device is directly connected to a central computer
         • usually through a switch
       • Can easily add to them
       • All nodes are independent
       • Allows high degree of security
       • its expensive to set up
   • WAN: Wide area network, any one is able to access it

4. The internet

   • A globally interconnected network of computers

5. Mesh network; how the large networks are connected

6. Peer to Peer networks

   • each devices shares the connection to the internet
     • this could be tablets, games consoles, computers
   • Each computer can give rights of access to other computers, so data can be shared
   • Typically used at home