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IP Addresses

Computer Science: OCR GCSE, topic 1.3.20

IP Addresses

Just as an address is essential for sending a letter in the post, Internet Protocol (IP) addresses are used to identify where data packets need to be sent to and where they have come from.

IP addresses

IP addresses

  • IP addresses are used by routers to determine whether a packet's destination is within the current network or not.
  • If not, then the router will pass the packet onto the wide area network (WAN), where other routers can use the IP address to figure out where to send the packet.
  • IP addresses are also used by network applications to specify which device they wish to communicate with.
Properties of an IP address

Properties of an IP address

  • IP addresses must be unique within the same local area network.
  • IP addresses do not need to be universally unique.

Types of IP Address

There are a few different types of IP addresses. This is because IP addresses are not universally unique.

IPv4 vs IPv6

IPv4 vs IPv6

  • There are two types of IP addresses:
  • IPv4 (version 4).
  • IPv6 (version 6).
  • IPv4 addresses are 32-bit numbers, often displayed as four numbers separated by dots. For example:
  • 73 . 124 . 131 . 67.
  • IPv6 addresses are 128-bit numbers, often displayed as eight groups of four hex digits. For example:
  • 2001 : 0db8 : 85a3 : 0000 : 0000 : 8a2e : 0370 : 7334.
Static IP vs dynamic IP

Static IP vs dynamic IP

  • IP addresses can either be static or dynamic.
  • A device with a static IP address will have the same IP address every time it connects to the network.
  • A device with a dynamic IP address will be allocated a new IP address every time it connects to the network.
  • Dynamic IP addresses are provided by the Dynamic Host Configuration Protocol (DHCP) server.
Private IP vs public IP

Private IP vs public IP

  • Devices within a local area network (LAN) can have private IP addresses.
  • These can be used to exchange data between devices on the LAN.
  • Routers which connect a LAN to a wide area network (WAN) also have a public IP address.
  • These are used when other networks on the WAN want to send data into the LAN of the router.

Test yourself on IP Addresses

  • Which piece of networking hardware uses IP addresses?

  • Routers use an IP address to determine what?

  • Which devices have a public IP address?

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