Network Topologies V2

Mesh Network
1. A network where some or all of the workstations or devices are connected directly to each other
2. Most devices are usually connected to the 'node' (device) that they exchange the most data with
3. If one device fails, not all data is lost
Star Network
1. A network where each device is individually connected via a single cable to the server
2. More commonly used in schools and offices
3. Very reliable; harder to hack
4. However, great amount of pressure is put on the Central Device
5. More expensive to set up
Wi-Fi (Wireless Frequency)
1. Radiowaves which are used to transmit packets
2. No need for wires and cables
3. Slower than Ethernet; more vulnerable to attack by hackers
4. Can be set up in remote locations e.g. Building, Planes etc.
Encryption
1. A method of scrambling data with a key code that doesn't make sense on its own
2. Can only be 'decrypted' (unscrambled) with a encryption key (same key used to 'encrypt' the device in the first place)
3. Encryption method used is called SSL (Secure Socket Layer); Used on websites e.g. Twitter
4. Makes it harder for hackers to hack encrypted data
Computer Network
1. A number of computers linked together to share resources with each other; Can share Hardware, Software, Data
2. Printers, Tablets, Laptops and Webcams can also be connected devices that work in a computer network
IP Address
1. A unique set of numbers separated by full stops
2. Identifies each computer or device using the Internet Protocol to communicate and interact with a network
3. Similar to a postcode to identify a house in a area
4. Sent with the packets to identify which computers are being sent data and where the data was sent from
5. Is broken down into 4 numbers which can represent a number between 0 and 255 separated with a full stop
6. IP Classes
  1. IP Addresses have different classes which identify the class of network which the user is on
  2. Indicates the number of total possible users and purpose of the network
7. Static IP - Never changes Dynamic IP - Periodically changes
MAC Address (Media Access Control Address)
1. Uniquely identifies a device on a network by identifying the network adapter that it is using
2. Allows you to distinguish between different devices
3. Unique code built into the NIC (Network Interface Card)
4. Embedded onto the device when made and cannot be changed by the user
5. Written individually and made up of 48 bits, normally in hexadecimal
Protocols
1. A set of rules or conventions which control the communication between devices on a network
2. Key Protocols
  1. TCP/IP (Transmission Control Protocol/ Internet Protocol)
    1. Used to transmit data between different networks
  2. HTTP (Hyper Text Transfer Protocol)
  3. HTTPS (Hyper Text Transfer Protocol Secure)
    1. Used when transferring files around the World Wide Web (websites etc.) HTTPS encrypts data, making it more secure
  4. FTP (File Transfer Protocol)
    1. Transfer files between computers on a network
  5. POP (Post Office Protocol)
    1. POP3 (Post Office Protocol v3)
      1. Retrieves mail; doesn't send email
  6. IMAP ( Internet Message Access Protocol)
    1. Retrieves and stores email messages on a mail server and allows you to manipulate them as if they were your own
  7. SMTP (Simple Mail Transfer Protocol)
    1. Transmits email over the Internet on mail servers (e.g. Yahoo, Gmail)
Packet Switching
1. Breaking down data into packets which are sent through the router and then reassembling it
2. Contains IP Address of sender and reciever
3. Contains Sequence Number (Order of Packets)
4. Contains time for when it's alive
5. 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
6. Packets are reassembled in the right order once all packets have been recieved
7. Contains Payload (actual data it's carrying)
8. Contains Error Detection Codes
9. Confirmation message is sent once all packets have recieved and placed in the right order
Layers
1. Where packets travel through while data is being recieved
2. Protocols manage the data which have gone through the layers, adding or removing data if necessary
3. If one layer fails/ not all layers are affected

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	Criado por 2402 2003 quase 7 anos atrás