A set of specifications for data transfer between devices on a local network. The standards describe packet-switching technology, protocols, and the physical implementation of the connection. Ethernet is the most common LAN technology.

It transfers data as frames — blocks of information consisting of a header and the transmitted data. The header specifies the MAC address of the sender and receiver, as well as other operational information. For reassembly of the individual frames into a single object, a checksum is applied. Frames are transmitted in broadcast mode, that is, to all nodes in the network. To reduce the amount of junk traffic and deliver packets only to the recipient in the header, special devices are used, namely routers.