1.4 Wireless and wired

1.4 Wireless and wired

1. LAN (Local Area Network)

   • Covers a small geographical area
   • Quite fast (100-1000 megabits per second)
   • Cheap
   • Used in Schools, Classes, Offices etc.
   • LANs are normally owned by the user

2. WAN (Wide Area Network)

   • Covers a large geographical area
   • Quite slow (Up to 150 megabits per second)
   • Used in Universities, Large Companies etc.
   • Might not own the WAN you use
   • Expensive
   • The Internet is a WAN

3. Transmission Media

   • What is used to connect/transfer data across different devices or the internet
   • Different Types
     • Ethernet
       • CAT5 & CAT6
       • Twisted-Pair Cable
         • Consists of two wires that wrap around each other
         • Least expensive
     • Fibre Optic
       • Made from glass; transfers data by light signals
     • Coaxial Cable
       • Central Wire surrounded by insulation and shielded by braided wire
     • Wireless
       • Radiowaves etc.

4. Router

   • An interconnection device used on networks to connect two or more devices
   • Identifies all devices connected to it with a number (IP Address)
   • Connects together different networks and forwards data packets along a network while also keeping packets running smoothly
   • Has a list of IP Addresses (Routing Table)

5. WAP (Wired Access Point)

   • A device that allows other devices to connect to a network using standards such as Wi-Fi, Bluetooth or Ethernet Cable

6. Switch

   • Allows devices to connect to each other
   • Has different ports for different devices to connect to each other
   • Filters and forwards data packets within a single network. This creates a direct connection between devices (intelligent)

7. Packets

   • Small packs of data broken down which is transmitted over a network
   • Each packet contains the IP address of the sender and IP address of the reciever
   • Contains a sequence number to be put back into order; not all packets get received at the same time or in the same order
   • Has a time to live (how many hops around the network before it disappears)
   • Chooses the cheapest (fastest) available path
   • Meta Data (Data providing information about other data) of Packets - Sequence Number, IP Addresses of Sender and Reciever, Time of packet being alive

8. NIC (Network Interface Card)

   • Built into a device which allows you to connect and 'talk' (communicate) to the internet
   • Allows data packets to travel to and from a computer
   • Contains a MAC Address which is a Physical Hardware Address (Permanent)
   • Allows an Ethernet Cable to be plugged in

9. Bottleneck - The delay in transmission of data through the circuits of a computer's microprocessor

10. DNS (Domain Name Server)

    • Has a list of domain names and their associated IP Addresses
    • Identifies the IP Addresses of websites
    • Without a DNS Server, we would have to remember the IP Addresses of websites that we access

11. VPN (Virtual Private Network)

    • Provides Privacy, Freedom and Security on the Internet
    • Allows to access and transfer files securely; protects it from hackers etc.
    • Also allows to access content which could be blocked or restricted in different countries
    • Can make it seem you are on the same network as other people even though you're not

12. Cloud

    • A collection of servers which store data and run applications
    • Can access files anywhere in the world
    • Increases storage for devices e.g. Mobile Phone
    • Can be used to collaberate with others from around the world

13. Virtual Network

    • Gives 'privileges' to