Network Topologies V2

Network Topologies V2

1. Mesh Network

   • A network where some or all of the workstations or devices are connected directly to each other
   • Most devices are usually connected to the 'node' (device) that they exchange the most data with
   • If one device fails, not all data is lost

2. Star Network

   • A network where each device is individually connected via a single cable to the server
   • More commonly used in schools and offices
   • Very reliable; harder to hack
   • However, great amount of pressure is put on the Central Device
   • More expensive to set up

3. Wi-Fi (Wireless Frequency)

   • Radiowaves which are used to transmit packets
   • No need for wires and cables
   • Slower than Ethernet; more vulnerable to attack by hackers
   • Can be set up in remote locations e.g. Building, Planes etc.

4. Encryption

   • A method of scrambling data with a key code that doesn't make sense on its own
   • Can only be 'decrypted' (unscrambled) with a encryption key (same key used to 'encrypt' the device in the first place)
   • Encryption method used is called SSL (Secure Socket Layer); Used on websites e.g. Twitter
   • Makes it harder for hackers to hack encrypted data

5. Computer Network

   • A number of computers linked together to share resources with each other; Can share Hardware, Software, Data
   • Printers, Tablets, Laptops and Webcams can also be connected devices that work in a computer network

6. IP Address

   • A unique set of numbers separated by full stops
   • Identifies each computer or device using the Internet Protocol to communicate and interact with a network
   • Similar to a postcode to identify a house in a area
   • Sent with the packets to identify which computers are being sent data and where the data was sent from
   • Is broken down into 4 numbers which can represent a number between 0 and 255 separated with a full stop
   • IP Classes
     • IP Addresses have different classes which identify the class of network which the user is on
     • Indicates the number of total possible users and purpose of the network
   • Static IP - Never changes Dynamic IP - Periodically changes

7. MAC Address (Media Access Control Address)

   • Uniquely identifies a device on a network by identifying the network adapter that it is using
   • Allows you to distinguish between different devices
   • Unique code built into the NIC (Network Interface Card)
   • Embedded onto the device when made and cannot be changed by the user
   • Written individually and made up of 48 bits, normally in hexadecimal

8. Protocols

   • A set of rules or conventions which control the communication between devices on a network
   • Key Protocols
     • TCP/IP (Transmission Control Protocol/ Internet Protocol)
       • Used to transmit data between different networks
     • HTTP (Hyper Text Transfer Protocol)
     • HTTPS (Hyper Text Transfer Protocol Secure)
       • Used when transferring files around the World Wide Web (websites etc.) HTTPS encrypts data, making it more secure
     • FTP (File Transfer Protocol)
       • Transfer files between computers on a network
     • POP (Post Office Protocol)
       • POP3 (Post Office Protocol v3)
         • Retrieves mail; doesn't send email
     • IMAP ( Internet Message Access Protocol)
       • Retrieves and stores email messages on a mail server and allows you to manipulate them as if they were your own
     • SMTP (Simple Mail Transfer Protocol)
       • Transmits email over the Internet on mail servers (e.g. Yahoo, Gmail)

9. Packet Switching

   • Breaking down data into packets which are sent through the router and then reassembling it
   • Contains IP Address of sender and reciever
   • Contains Sequence Number (Order of Packets)
   • Contains time for when it's alive
   • If not all packets are recieved, an error message is sent and the packets are resent, if that still does't work, then packets are deleted
   • Packets are reassembled in the right order once all packets have been recieved
   • Contains Payload (actual data it's carrying)
   • Contains Error Detection Codes
   • Confirmation message is sent once all packets have recieved and placed in the right order

10. Layers

    • Where packets travel through while data is being recieved
    • Protocols manage the data which have gone through the layers, adding or removing data if necessary
    • If one layer fails/ not all layers are affected