Ethernetteknik

Ethernetteknik refers to the family of networking technologies used to build local area networks (LANs) based on Ethernet standards. It covers the data link and physical layers for transmitting data in frames over copper or fiber media.

The technology originated in the 1970s at Xerox PARC and was standardized by the IEEE as 802.3. Early implementations used coaxial cables and CSMA/CD to manage access; modern Ethernet primarily uses switched networks and full duplex operation, which reduces collisions and increases performance.

Typical media include twisted-pair copper (for example RJ-45 connections) and various forms of fiber optic cables. Standards have evolved from 10 Mbps (10BASE-T, 10BASE-F) to 100 Mbps (Fast Ethernet, 100BASE-TX), 1 Gbps (Gigabit Ethernet, 1000BASE-T), 10 Gbps (10GBASE-T, 10GBASE-SR/LR), and higher speeds such as 25GBASE, 40GBASE, and 100GBASE, which are common in data centers and core networks.

Operation is commonly based on a star topology with switches at the center; hubs, once common in early Ethernet, are largely obsolete in modern networks. In legacy half-duplex Ethernet, CSMA/CD governs access; in switched, full-duplex networks, collisions are minimized and flow control is used to manage traffic. Ethernet frames contain a destination and source MAC address, EtherType or length, payload, and a CRC. Features include auto-negotiation, link aggregation (LACP), VLAN tagging (IEEE 802.1Q), quality of service (QoS), and Power over Ethernet (IEEE 802.3af/at/bt).

Ethernet remains the dominant LAN technology due to its scalability, cost-effectiveness, and broad ecosystem, serving applications from home networks to large data centers.