Ethernet, also known as IEEE 802.3, is a widely used networking technology that defines the standards for the physical and data link layers of a wired local area network (LAN). It governs how devices communicate and share data over a network using Ethernet frames. Here are some key aspects of Ethernet (IEEE 802.3):

  1. Data Link Layer: Ethernet operates primarily at the data link layer (Layer 2) of the OSI model. It provides the mechanisms for addressing devices on the network and controlling how data is placed onto the network medium.
  2. Physical Media: Ethernet supports various physical media for data transmission, including twisted-pair cables (e.g., Cat5e, Cat6), fiber-optic cables, and coaxial cables (older implementations). The choice of medium depends on factors like data rates, distance, and network requirements.
  3. Ethernet Frames: Data is transmitted over Ethernet networks in units called frames. An Ethernet frame consists of various fields, including source and destination MAC addresses, type/length field, data payload, and cyclic redundancy check (CRC) for error detection.
  4. MAC Address: Each device on an Ethernet network is assigned a unique Media Access Control (MAC) address. MAC addresses are used to identify devices and ensure that frames are delivered to the correct destination.
  5. CSMA/CD: Ethernet originally used the CSMA/CD (Carrier Sense Multiple Access with Collision Detection) access method. This method helps manage access to the network medium and handle collisions when multiple devices try to transmit simultaneously. However, modern Ethernet networks (e.g., full-duplex connections) do not rely on CSMA/CD due to increased speeds and reduced collision likelihood.
  6. Data Rates: Ethernet standards define different data rates, such as 10 Mbps (Ethernet), 100 Mbps (Fast Ethernet), 1 Gbps (Gigabit Ethernet), 10 Gbps (10 Gigabit Ethernet), and higher speeds.
  7. Ethernet Switching: Ethernet switches have largely replaced hubs in modern networks. Switches use MAC addresses to intelligently forward frames only to the intended recipient device, reducing network congestion and improving performance.
  8. Evolution: Ethernet has evolved over the years to accommodate higher data rates, improved error handling, and support for various physical media. It continues to adapt to the changing demands of networking technology.

Ethernet is a foundational technology that enables reliable and efficient communication within local area networks. Its widespread adoption has made it an integral part of modern computing and communication environments.