Ethernet Basics -9

MAC Addresses

• MAC address (physical address)

• In a Local Area Network (LAN) or other network, the MAC (Media Access Control) Address is the unique address of your computer or of the other nodes, which have a unique hardware number.

• The MAC address is used by the Data-Link Layer of the OSI reference model.

• One might equate a MAC address to a fingerprint.

MAC addressing

• MAC address

• Is unique within a network (worldwide)• Layer 2 (Data-Link) address• 2566 or 2.81 x 1014 different addresses

(281,474,976,710,656)• Manufacturer Portion + Component portion

MAC addressing

An example of a MAC Address is:00:70:6A:0E:1D:5C

• MAC address ( Physical address)

• MAC addresses are made up of 6 Bytes or 48 Bits

• A Bit is one digit, either zero or one (0-1)

• A Byte consists of 8 Bits – a combination of zeros and ones.

MAC addressing

MAC addressing

• MAC address

• The 48 BIT address is depicted in its HEX format, six groups separated by colons (:).

• 00:70:6A:0E:1D:5C

• Each of the HEX groupings represents a string of 6 binary octets. The above address is a string of 0's and 1's.

• 00000000.01110000.01100011.00001110.00011101.01011101

• MAC address (Physical address)

• Part of the MAC address represents the manufacturer and the other part represents the specific device from that manufacturer.

• Manufacturer Portion Device Portion• 00:70:6A 0E:1D:5C

• The Manufacturer portion will remain the same for any device from that manufacturer unless there are multiple manufacturer ID's for one company. The device portion will be different from one device to the next.

MAC addressing

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