MAC - Media Access Control

The MAC Address is also known as the hardware address, which is used to identify each system on the local network, ex. Ethernet. The MAC address is usually encoded on the Network Interface Card (NIC) of the system found on the motherboard. It is a unique 48-bit alphanumeric address that remains different for all the systems in the world.

Media Access Control is the bottom-most layer of the two sublayers, in the Data Link layer of the OSI reference model. It interfaces directly with  the network medium, i.e. the Physical layer. The other sub-layer that resides at the data link layer is the Logical Link Control (LLC) layer, that  communicates with the network layer.

How to find the MAC address of a system?
It is a 48-bit alphanumeric code which is encoded on the hardware of the device. In a windows system, a MAC address could be identified with the  help of the "ipconfig /all" command. This command could be executed from the 'command mode' of the windows operating system.

A typical Hardware/Physical address might look something like this:-
Physical Address......: 22-32-12-65-A1-B6
Here, the first half of the address "22-32-12" represents the ID number of the manufacturer and the next half "65-A1-B6" is the serial number assigned by the  manufacturer.