Meaning & Definition
Ethernet is a widely used and well-established set of technologies and protocols for local area networks (LANs) that allow computers and devices to communicate and share data over a physical network. It was developed in the 1970s and has evolved over the years to become the most common networking technology used in LANs, connecting devices within a limited geographical area, such as a home, office, or campus.
Here are some key aspects of Ethernet:
- Physical Connection
Ethernet uses physical cables to connect devices within a network. These cables can be copper-based (e.g., twisted-pair cables) or fiber-optic, depending on the specific requirements of the network.
- Data Link Layer
Ethernet operates at the data link layer of the OSI (Open Systems Interconnection) model, which is responsible for framing, addressing, and error detection in data transmission. Ethernet frames data in a standardized format and uses Media Access Control (MAC) addresses to identify devices on the network.
- Ethernet Standards
Ethernet has seen numerous standardization efforts over the years, resulting in different variations or “flavors” of Ethernet. Some of the most common Ethernet standards include:
- 10BASE-T: 10 Mbps Ethernet over twisted-pair copper cables.
- 100BASE-T (Fast Ethernet): 100 Mbps Ethernet over twisted-pair cables.
- 1000BASE-T (Gigabit Ethernet): 1 Gbps Ethernet over twisted-pair cables.
- 10GBASE-T (10 Gigabit Ethernet): 10 Gbps Ethernet over twisted-pair cables.
- 1000BASE-SX and 1000BASE-LX (Gigabit Ethernet over Fiber): 1 Gbps Ethernet over fiber-optic cables.
Ethernet networks often use network switches to manage data traffic. Switches use MAC addresses to forward data packets only to the specific devices that need them, which improves network efficiency.
- Collision Detection
Traditional Ethernet used a contention-based system called Carrier Sense Multiple Access with Collision Detection (CSMA/CD) to manage data collisions on shared networks. However, in modern Ethernet networks, full-duplex communication and switches have largely eliminated the need for collision detection.
- Internet Connectivity
Ethernet is commonly used to connect local networks to the Internet. This is typically achieved through network routers or gateways that connect the local Ethernet network to a wide area network (WAN), such as the Internet.
- LAN Topologies
Ethernet supports various LAN topologies, including star, bus, and ring configurations. In modern Ethernet networks, the star topology (using switches) is the most common.
- Wireless Ethernet
Wi-Fi, which is commonly used for wireless LANs, also follows Ethernet protocols but operates over radio waves rather than physical cables.
Ethernet is known for its reliability, speed, and robustness, making it the foundation of most wired LANs. It is used in a wide range of applications, from home networks to enterprise networks and data center environments. As technology continues to advance, Ethernet standards have continued to evolve, with ever-increasing speeds and capabilities to meet the growing demands of modern networks.