Ethernet is the most used networking technology for LANs today. It defines wiring and signaling for the Physical layer of the OSI model. For the Data Link layer, it defines frame formats and protocols.
Ethernet is described as IEEE 802.3 standard. It uses Carrier Sense Multiple Access with Collision Detection (CSMA/CD) access method and supports speeds up to 100 Gbps. It can use coaxial, twisted pair and fiber optic cables. Ethernet uses frames to with source and destination MAC addresses to deliver data.
The term Ethernet LAN refers to a combination of computers, switches, and different kinds of cables that use the Ethernet standard to communicate over the network. It is by far the most popular LAN technology today.
Ethernet is the traditional technology for connecting wired local area networks (LANs), enabling devices to communicate with each other via a protocol — a set of rules or common network language.
As a data-link layer protocol in the TCP/IP stack, Ethernet describes how network devices can format and transmit data packets so other devices on the same local or campus area network segment can recognize, receive and process them. An Ethernet cable is the physical, encased wiring over which the data travels.
Any device accessing a geographically localized network using a cable — i.e., with a wired rather than wireless connection — likely uses Ethernet — whether in a home, school or office setting. From businesses to gamers, diverse end users depend on the benefits of Ethernet connectivity, including reliability and security.
Compared to wireless LAN technology, Ethernet is typically less vulnerable to disruptions — whether from radio wave interference, physical barriers or bandwidth hogs. It can also offer a greater degree of network security and control than wireless technology, as devices must connect using physical cabling — making it difficult for outsiders to access network data or hijack bandwidth for unsanctioned devices.
How Ethernet works
The Institute of Electrical and Electronics Engineers Inc. (IEEE) specifies in the family of standards called IEEE 802.3 that the Ethernet protocol touches both Layer 1 — the physical layer — and Layer 2 — the data link layer — on the OSI network protocol model. Ethernet defines two units of transmission: packet and frame. The frame includes not just the payload of data being transmitted, but also:
- the physical media access control (MAC) addresses of both the sender and receiver;
- VLAN tagging and quality of service information; and
- error correction information to detect transmission problems.
Each frame is wrapped in a packet that contains several bytes of information to establish the connection and mark where the frame starts.
Engineers at Xerox first developed Ethernet in the 1970s. Ethernet initially ran over coaxial cables, while a typical Ethernet LAN today uses special grades of twisted pair cables or fiber optic cabling. Early Ethernet connected multiple devices into network segments through hubs — Layer 1 devices responsible for transporting network data — using either a daisy chain or star topology.