What Is Mac Address? Explained With Formatting Examples

What Is Mac Address? Explained With Formatting Examples

The MAC address (Media Access Control Address) is a string of some binary numbers used to identify computer network adapters. MAC address is just like your home address. This is used for identifying devices. MAC address is embedded into the network hardware during the manufacturing process, or stored in firmware, and designed to not be changed or modified.

Some also refer to MAC address as "Ethernet addresses" for historical reasons, but multiple types of networks all utilize MAC addressing including Ethernet, Wi-Fi, and Bluetooth.
What Is Mac Address? Explained With Formatting Examples
What Is Mac Address? Explained With Formatting Examples

The Format of a MAC Address

Traditional MAC addresses are 12-digit (6 bytes or 48 bits) hexadecimal numbers. By convention, they are generally written in one of the following three formats:

MM-MM-MM-SS-SS-SS

MM:MM:MM:SS:SS:SS

MMM.MMM.SSS.SSS

Left 6 digits (24 bits) called a "prefix" is associated with the adapter manufacturer. Each vendor registers and obtains MAC prefixes as assigned by the Institute of Electrical and Electronics Engineers. Vendors often possess many prefix numbers associated with their different products. For example, the prefixes 00:11:10, 00:22:8E and 55:7G:56 (plus many others) all belong to Linksys (Cisco Systems).

The right 4 digits of a MAC address represent an identification number for the specific device. Among all devices manufactured with the same vendor prefix, each is given their own unique 24-bit number. Note that hardware from different vendors may happen to share the same device portion of the address.

64-bit MAC Addresses Explained

While traditional MAC addresses are all 48 bits in length, a few types of networks require 64-bit addresses. ZigBee home automation and other similar networks based on Institute of Electrical and Electronics Engineers 802.15.4, for example, require 64-bit MAC addresses be configured on their hardware devices.

Transmission Control Protocol Or Internet Protocol networks based on IPv6 also implement a different approach to communicating MAC addresses compared to mainstream IPv4. Instead of 64-bit hardware addresses, though, IPv6 automatically translates 48-bit MAC address to a 64-bit address by inserting a fixed 16-bit value FFFE in between the vendor prefix and the device identifier. IPv6 calls these numbers "identifiers" to differentiate them from true 64-bit hardware addresses.

For example, a 48-bit MAC address 00:25:96:12:34:56 appears on an IPv6 network as (commonly written in either of these two formats):

00:25:96:FF:FE:12:34:56

0025:96FF:FE12:3456

MAC Address (Media Access Control Address) vs. IP Address (Internet Protocol) Relationship

TCP/IP networks use both MAC addresses and IP addresses but for separate purposes. A MAC address remains fixed to the device's hardware while the IP address for that same device can be changed depending on its TCP/IP network configuration. Media Access Control operates at Layer 2 of the OSI model while Internet Protocol operates at Layer 3. This allows MAC addressing to support other kinds of networks besides TCP/IP.

IP networks manage the conversion between IP and MAC addresses using Address Resolution Protocol (ARP). The Dynamic Host Configuration Protocol (DHCP) relies on ARP to manage the unique assignment of IP addresses to devices.

What Is Cloning Of MAC Address?

Some ISP's link each of their residential customer accounts to the MAC addresses of the home router or another gateway device. The address seen by the provider does not change until the customer replaces their gateway, such as by installing a new router. When a residential gateway is changed, the Internet Service Provider now sees a different MAC address being reported and blocks that network from going online.

Cloning Of A MAC Address is solved this problem by enabling the router or gateway to keep reporting the old MAC address to the ISP even though its own hardware address is different. 

Administrators can configure their router to use the MAC Address cloning option and enter the MAC address of the old gateway into the configuration screen. When cloning is not available, the customer must contact the service provider to register their new gateway device.
What Is Mac Address? Explained With Formatting Examples What Is Mac Address? Explained With Formatting Examples Reviewed by Technowap on May 23, 2019 Rating: 5

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