MAC Addresses
Computer Science: OCR GCSE, topic 1.3.21
MAC Addresses
Every network interface controller (NIC) has a globally unique media access control (MAC) address.
MAC Address
- Every network interface controller (NIC) has a globally unique media access control (MAC) address.
- MAC addresses are assigned when a device is manufactured and cannot be changed once they are assigned.
- A device with multiple interfaces (e.g. a computer with both WiFi and Ethernet capability) will have multiple MAC addresses.
Uses of MAC addressing
- MAC addresses can be used to exchange data on the same local area network (LAN).
- MAC addresses are also used by switches and NICs to send data to the intended recipient.
MAC address format
- MAC addresses used to be 48-bit numbers, although some 64-bit versions have been introduced.
- MAC addresses are represented as pairs of hexadecimal digits. For example:
- B8:8D:12:58:77:32 .
- MAC addresses have a specific format:
- The first half of the address relates to the manufacturer of the device. This would be B8:8D:12 in the example above.
- The remaining half relates to the individual device that has been produced.
Test yourself on MAC Addresses
Are MAC addresses unique globally or locally?
What does the first half of a MAC address specify?
Which of these statements about MAC addresses are true?