CHAPTER 9

CHAPTER 9

Ethernet is can be found in layer 1 and layer 2 or the Physical layer 1 and Data Link layer2 in the OSI model. The Data Link layer is divided into two sub layer the Logical Link Control (LLC) and  Media Access Control (MAC). The LLC is in the upper portion of Data Link sub layer and the IEEE describes LLC as 802.2 that communicates up to the upper layers which is the inter action of the hardware and the software it acts as a driver of the NIC (Network Interface Card). The LLC is the one responsible for transmitting and communicating to the upper layers which is in the hardware portion and the one who transmit data into media access control going to the lower layer which is the physical.

                The Media Access Control (MAC) is in the lower portion in the Data Link sub layer. The IEEE describes MAC address as 802.3.

                In the world of networking every device was connected in the same shared network, e.g. Local Area Network, Wide Area Network, Wireless network.

All computers are connected with each other but the confusing question is how could you identify that this message or data is for you.? Since the signal is sent to every device that is connected to a network. In the OSI model layer 2 in Data Link layer specifically the lower part of the sub layers the (MAC) Media Access Control takes place and will answer this question.

Media Access Control address is a unique identifier that assists and help to determine between the source and the destination in an Ethernet network, regardless of what type or name of Ethernet use as long as it was an Ethernet, from MAC going to its lower layer which is the physical their role is for identifying and naming for each device type.

What is the process of creating MAC address? How?

The Institute of Electrical and Electronic Engineers (IEEE) enforced the rules of requiring all vendors that sells Ethernet devices to register with IEEE, and then the IEEE will assign a unique 3-byte code the (OUI) Organizational Unique Identifier.

(e.g.) 00 60 2F

The vendor also create their 3-byte code             

(e.g.) 3A 07 BC

And combine them together that will result the MAC address (00-60-2F-3A-07-BC). The MAC is now created then the vendor will now burn the MAC address into the chip ROM (Random Access Memory) in the NIC (Network Interface Card) that makes the MAC address permanently unique and cannot be change and alter by any software or user, therefore in every NIC (Network Interface Card) that have Ethernet ports contains unique MAC address (Media Access Control) address.