Full form of MAC
Full form of MAC is Media Access Control Address.
MAC address is the hardware identification number which identify each device connected to the network. The MAC address is fixed into Network Interface Cards (NIC) in computer at the time of manufacturing like, Ethernet card, Wi-Fi card, so it can’t be changed. and some well known manufacturers are such as, Nortel, Dell, Belkin and Cisco. The default given address of the device can be changed by replacing the NIC cards.
It is also known as a physical address or hardware address of the network device.
History of MAC
As per the history says, the existence of Media Access Control addresses are created by Xerox PARC scientists.
There are several other similar names also used instead of MAC address such as, physical address, hardware address, Ethernet hardware address of the network device.
BIA (Burned-In Address) specially for Cisco Router Switches are also known as the same.
Characteristics of MAC
The MAC address referred as hardware identification number is globally unique number and which used to identify the each device in the network.
The total length of MAC address is in 48 bits or 6 bytes. and can be written like this,
Six-Two digits group hexadecimals separated by hyphens (-), like 56-79-89-BC-23-DC
Six-Two digits group hexadecimals separated by colons (:), like 56:79:89:DC :BC:23
Three-Four digits group hexadecimals separated by dots (:), like WXYZ.3456.1456
The address bits of 24 bits(4 bytes) is known as Organizationally Unique Identifier (OUI) Number. and the Internet Assigned Number Authority (IANA) assigns this OUI number.
The devices such as, NIC cards, Switches and Bridges are existed on this second layer and for error free data transmission this layer is also responsible.
Advantages
The devices has no or free cost which connected to the network.
The policy has set on the devices switches or routers. whether it has authorized equipment or non-authorized equipment attached regardless the person attaching it.
For all the devices, the MAC addresses on the same network can be different. Thus, diagnose of network issues are easy.
To identify the senders and receivers of the data on network, it is reliable with the help of MAC address.
The MAC addresses are not changed from time to time, unlike the dynamic IP addresses.
Disadvantages
Since the first three bytes of MAC address are occupied for the manufacturer, so the size is limited only be 2 ^ 24 unique address per OUI.
For MAC address sorting, there can be spoofing is easy. and because of the broadcast nature of Ethernet, one can act unrecognizable and can listen to and from authorized MAC addresses.
Generally, there is chance to gain access to the network by attacker by continuely changing his MAC address.