The use of the MAC address is one of the most important aspects of the Ethernet LAN technology. MAC addresses use hexadecimal numbering.

Hexadecimal is a word that is used both as a noun and as an adjective. When used by itself (as a noun) it means the hexadecimal number system. Hexadecimal provides a convenient way to represent binary values. Just as decimal is a base ten number system and binary is a base two number system, hexadecimal is a base sixteen system.

The base sixteen number system uses the numbers 0 to 9 and the letters A to F. Figure 1 shows the equivalent decimal and hexadecimal values for binary 0000 to 1111. It is easier for us to express a value as a single hexadecimal digit than as four binary bits.

Given that 8 bits (a byte) is a common binary grouping, binary 00000000 to 11111111 can be represented in hexadecimal as the range 00 to FF. Leading zeroes are always displayed to complete the 8-bit representation. For example, the binary value 0000 1010 is shown in hexadecimal as 0A.

Note: It is important to distinguish hexadecimal values from decimal values regarding the characters 0 to 9, as shown in Figure 1.