But all the above mentioned 3 name numbering systems have the similar layout. But this target of addresses production is controlled and handled by the IEEE (institute of electrical and electronics engineers) who claimed EUI (Extended Unique Identifier)-48 and EUI (Extended Unique Identifier)-64 names as their trademarks. Besides these, MAC addresses will be produced in accordance with the one of the following 3 name spaces numbering rules: MAC-48, EUI-48, and EUI-64 rules. But remember, only one unique MAC address will be assigned to every NIC device in this situation. A computer if it is a host then can have more than one NIC. In case, if manufacturers are the authorities to assign them, then MAC address will known as “burned-in address” or “EHA (Ethernet hardware address). Anyhow, these addresses are resided in the card’s ROM (read-only memory) or somewhere else in the firmware instruments. Such addresses are usually assigned by the NIC manufacturer of a network. MAC as the data link layer’s sublayer protocol is the important logical portion of OSI reference model. Well! These addresses can be employed with different network technologies such as IEEE 802. Picture 1 – Structure od the MAC address – source: It is also called a Media Access Control (MAC) address, since the Ethernet media access control system includes the frame and its addressing. The resulting 48-bit address is often called the hardware, or physical, address to make the point that the address has been assigned to the Ethernet interface. This is mostly done by giving the next 24 bits in order from 1 to 2 24. The vendor then assigns the next 24 bits, being careful to ensure that each address is unique. Where is the other 24 bits, MAC is 48 bits?Ī manufacturer of Ethernet interfaces creates a unique 48-bit Ethernet address for each interface by using their assigned OUI for the first 24 bits of the address. This also eliminates any need to locally administer and manage Ethernet addresses. Providing unique addresses during manufacturing avoids the problem of two or more Ethernet interfaces in a network having the same address. This allows a vendor of Ethernet equipment to provide a unique address for each interface they build. Then the vendors must use this 24-bit as a start for every MAC address of their network product interface card. This blocks of addresses for use by network vendors, the OUI is a unique 24-bit identifier assigned to each organization that builds network interfaces. The IEEE-SA provides a 24-bit Organizationally Unique Identifier (OUI) to the vendors. Structure of the MAC address and who is making it?Īssignment of addresses is controlled by the IEEE Standards Association (IEEE-SA), which administers a portion of the address field. For the proper and to the point communication between a network’s computers, MAC address is used to identify uniquely each network interface.
An Ethernet MAC address is a 48-bit binary value expressed as 12 hexadecimal digits.īoth media access control and medium access control are the elaborated forms of the same term “MAC” address. MAC addressing is added as part of a Layer 2 ethernet frame. So we can say that unique identifier called a Media Access Control (MAC) address was created to help in finding the source and destination address in an Ethernet network. When two end devices communicate on the local Ethernet network, the frames that are exchanged between them contain the destination and source MAC addresses. In a LAN using Ethernet, this address is called the Media Access Control (MAC) address. The Layer 2 address is unique on the local network and represents the address of the end device on the physical media. MAC address, what that means and what MAC address actually is?
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