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Computer Science GCES OCR

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  1. Cpu Architecture Performance And Embedded Systems Ocr
    5 主题
  2. Primary And Secondary Storage Ocr
    6 主题
  3. Data Storage And Compression Ocr
    12 主题
  4. Networks And Topologies Ocr
    6 主题
  5. Wired And Wireless Networks Protocols And Layers Ocr
    6 主题
  6. Identifying And Preventing Threats To Computer Systems And Networks Ocr
    2 主题
  7. Operating Systems And Utility Software Ocr
    2 主题
  8. Ethical Legal Cultural And Environmental Impact Ocr
    2 主题
  9. Computational Thinking Searching And Sorting Algorithms Ocr
    3 主题
  10. Designing Creating And Refining Algorithms Ocr
    5 主题
  11. Programming Fundamentals And Data Types Ocr
    5 主题
  12. Additional Programming Techniques Ocr
    7 主题
  13. Defensive Design And Testing Ocr
    6 主题
  14. Boolean Logic Diagrams Ocr
    2 主题
  15. Programming Languages And Integrated Development Environments Ides Ocr
    3 主题
  16. The Exam Papers Ocr
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  17. Structuring Your Responses Ocr
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Exam code:J277

  • Devices on a network send and receive data, a device needs an address to ensure it sends data to the correct place

  • There are two types of network address systems:

    • IP Address

    • MAC Address 

IP Addressing

What is an IP address?

  • An IP (Internet Protocol) address is a unique identifier given to devices which communicate over the Internet (WAN)

  • IP addresses are dynamic, they can change

  • IP addresses make it possible to deliver data to the right device

  • A device connecting to a network will be given an IP address, if it moves to a different network then the IP address will change

IPv4

  • Internet Protocol version 4 is represented as 4 blocks of denary numbers between 0 and 255, separated by full stops

  • Each block is one byte (8 bits), each address is 4 bytes (32 bits)

ipv4
  • IPv4 provides over 4 billion unique addresses (232), however, with over 7 billion people and countless devices per person, a solution was needed

IPv6

  • Internet Protocol version 6 is represented as 8 blocks of 4 hexadecimal digits, separated by colons

  • Each block is 2 bytes (16 bits), each address is 16 bytes (128 bits)

-ipv6
  • IPv6 could provide over one billion unique addresses for every person on the planet (2128)

MAC Addressing

What is a MAC address?

  • A MAC (Media Access Control) address is a unique identifier given to devices which communicate over a local area network (LAN)

  • MAC addresses are static, they can never change

  • MAC addresses make it possible for switches to efficiently forward data to the intended recipient

  • Any device that contains a Network Interface Card (NIC) has a MAC address assigned during manufacturing

  • A device connecting to a local network already has a MAC address, if it moves to a different network then the MAC address will stay the same

mac-address-1
  • A MAC address is represented as 12 hexadecimal digits (48 bits), usually grouped in pairs

  • The first three pairs are the manufacturer ID number (OUI) and the last three pairs are the serial number of the network interface card (NIC)

  • There are enough unique MAC addresses for roughly 281 trillion devices

Worked Example

Computers in a network can be identified using both IP addresses and MAC addresses.

Describe two differences between IP addresses and MAC addresses [2]

Answer

  • IP address is dynamic/can change // MAC address is static/cannot change

  • IP address is used to communicate on a WAN/Internet // MAC address is used to communicate on a LAN

Responses

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