1.5 topologies

1.5 topologies

1. packet switching

   • cant send all through at once
   • take it apart and send it bit by bit
   • if you need to send a photo it is first broken down into
     • each packet is given a header which contains the IP address of the network and device being sen to
       • it also contains the IP address of the device it was sent from
       • the header also contains the packet number eg packet 4/60 or 56/60
         • when the packets arrive at their destination the information is used to re assemble the data
           • packets are sometimes lost on the way to their destination and if it does then the computer requests for it to be sent
           • if a packet doesn't arrive then it is deleted from the router

2. a computing network =group of computers that are lnked together and allows them to share resources

   • networking computers can share hardware software and data

3. IP number

   • this is a unique string of numbers that are separated by full stops
   • it identifies each computer using the internet protocol to communicate over a network
   • it is like a postcode which is used to identify a house in a county on a street
   • eg 749.826.3.59
   • different classes that identify which network it is on

4. MAC address

   • media access control address
   • uniquely identify a device on a network by identifying the network adapter the device is using
   • embedded in device when manufactured, cannot be changed
   • unique code which is built into the Network interface Card (NIC)
     • each address is individual and is made up of 48 bits (hexadecimal)

5. mesh network

   • all workstation or devices are connected directly to each other
   • most are connected with a node to send data

6. star network

   • each connected by individual cable to server
     • if individual cable is broken then that computer is unable to request from the server
       • however it doesn't affect the rest of the computers
   • layout in choice in schools and offices
     • tend to be most reliable

7. WiFi-wireless frequency

   • radio waves are used to transmit data packets
   • slower and more vulnerable to attack
     • but removes need for cables and networks
   • but this means it can be set up in remote locations like planes, cars, parks etc

8. encrption

   • a method of scrambling data that makes no sence
   • in an open WiFi anyone can sniff out and steal packets from other users
   • ecryption makes it so that if any of the data is stolen then it will make no sence
   • the only way to decrypt the scrambled data is with the key which only the receiver has

9. compression

   • lossy
     • original file cannot be recreated as data is lost
   • lossless
     • no data lost so original file can be recreated