MAC address (CIE IGCSE Computer Science)

• A Media Access Control/MAC address is used to identify a device on a network
• It is a unique code which consists of six pairs of hexadecimal codes separated by a colon
• Each pair of hex digits is a Byte of data. So in total a MAC address is 6 bytes or 48 bits long
• An example MAC address is b4:71:ac:f3:21:a2
• The MAC address is assigned to the NIC by its manufacturer
• The first three pairs are the manufacturer ID number and the last three pairs is the serial number of the NIC and identifies the device on the network
   

An example MAC address - the first part identifying the manufacturer and the second part identify the device

• A MAC address cannot be changed. It is static

A table listing the differences between an IP address and a MAC address

MAC Address	IP Address
Permanently assigned to a NIC and cannot be changed	Can be used to identify devices on a network but are dynamic and can be changed
MAC addresses are written in hexadecimal	IP addresses  are written in denary
MAC addresses are 6 bytes long	IP addresses are 4 bytes long
MAC addresses are used to identify a device on a LAN	IP addresses are used to identify a device on a  WAN