A protocol through which two connected devices can communicate common capabilities, for example, speed and duplex mode, to each other. Once common capabilities are communicated, the highest common capabilities for both devices, for example, 100 Mbps and full-duplex mode, are chosen as the operating modes.
Enabling two devices that share a common link to advertise their speed capabilities, acknowledge receipt and understanding of shared modes of operation, and reject modes of operation that are not shared.
Autonegotiation (formerly NWay) is an Ethernet procedure by which two connected devices choose common transmission parameters, such as speed and duplex mode. In this process, the connected devices first share their capabilities as for these parameters and then choose the fastest transmission mode they both support.