4.1 Ethernet

Question 1

ETHERNET PROTOCOL

Answer 1

Ethernet protocols define how data is formatted and how it is transmitted over the wired network.
The Ethernet standards specify protocols that operate at Layer 1 and Layer 2 of the OSI model.

IEEE 802.3

Question 2

MAC Address

Answer 2

Media Access Control
The MAC Address identifies each source and destination host on the network.

Every computer on an Ethernet local network has a Media Access Control (MAC) address that is burned into the Network Interface Card (NIC).
Computer MAC addresses are usually displayed as 6 sets of two hexadecimal numbers separated by dashes or colons.

Every Ethernet network interface has a physical address assigned to it when it is manufactured.
These addresses are 48 bit (6 bytes) long and are written in hexadecimal notation.
MAC addresses are made up of two parts.
One part of the MAC address, the first 3 bytes, represents the vendor who manufactured the network interface.
This part of the MAC is called the OUI (Organizationally Unique Identifier).
Each vendor who wants to make and sell Ethernet network interfaces must register with the IEEE in order to be assigned an OUI.

The second part of the address, the remaining 3 bytes are the unique ID for the interface.
All MAC addresses that begin with the same OUI must have unique values in the last 3 bytes.