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What is Ethernet?

Ethernet is a widely used technology for connecting computers, servers, routers, switches, and other network devices within a local area network (LAN) or, more broadly, in a larger network infrastructure. It defines a set of standards for the physical and data link layers of the OSI network model, enabling devices to communicate over a shared or dedicated network medium.

Key features of Ethernet

Physical Connectivity

Ethernet can operate over various physical mediums, including twisted-pair copper cables, fibre optic cables, and wireless connections. The most common form is Ethernet over twisted-pair cables.

Data Link Layer Protocol

Ethernet uses a protocol at the data link layer, with the most prevalent version being the Ethernet II frame format. This frame format includes source and destination MAC (Media Access Control) addresses, type information, and payload data.

CSMA/CD (Carrier Sense Multiple Access with Collision Detection)

In the past, Ethernet networks used CSMA/CD as a protocol to manage access to the shared communication medium (e.g., a coaxial cable). However, with the widespread use of switched Ethernet, CSMA/CD is no longer commonly used.

Switched Ethernet

In modern Ethernet networks, especially in LANs, the traditional shared medium has been largely replaced by switched Ethernet. Switches allow devices to communicate more efficiently by creating dedicated communication paths between devices, eliminating collisions and increasing network performance.

Data Transmission Speeds

Ethernet supports various data transmission speeds, such as 10 Mbps (Ethernet), 100 Mbps (Fast Ethernet), 1 Gbps (Gigabit Ethernet), 10 Gbps, 25 Gbps, 40 Gbps, and 100 Gbps, with ongoing developments for higher speeds.


The Institute of Electrical and Electronics Engineers (IEEE) plays a crucial role in standardising Ethernet technologies. The IEEE 802.3 standard defines the specifications for Ethernet networks.

Ethernet is the backbone of most local area networks, providing a reliable and scalable means of interconnecting devices within a confined geographic area. It has evolved over the years to accommodate higher speeds, improve efficiency, and adapt to changing networking requirements.

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