Everything you need to know about a MAC address, the media access control address
What is a MAC Address?
“MAC” is an acronym for media access control. MAC addresses are unique identifiers for electronic network devices that are capable of connecting to the Internet. MAC addresses are assigned to the manufacturer of any network interface card. This is different from an IP address. IP addresses identify the main device on a network. On the other hand, MAC addresses identify the network adapter for that device.
For example, let’s say your smart phone is connected to your home router via Wifi. Your smart phone has an internal wireless radio that communicated directly with the router. Your phone has an IP address on the network. The MAC address is assigned to the wireless radio. The router uses the MAC address to correctly identify the wireless smart phone and relays responses to and from the device.
MAC Address Formats
Mac addresses are represented as 48-bit hexadecimal string, as determined by the IEEE 802 MAC Address Standards. The notation for the address is usually 6 pairs of hexadecimal characters separated by colons (:). Alternatively, MAC addresses can also be represented using hyphens/dashes (-) as separators. The figures below are a graphical depiction of MAC addressing formats.
Each pair of digits in the address represents 1 byte, for a total of 6 bytes. There are 8-bits represented by each byte. Therefore to get the total bits for the address, you can multiply the number of bits by the number of bytes, yielding 48 total bits. The first three bytes, and therefore the first half of the MAC address, is used to represent the Organizationally Unique Identifier. This group of characters identifies the manufacturer of the network interface card for the device. The second three bytes, the last half of the entire address, represents the network interface controller. This group of characters uniquely identifies the network interface controller itself.