A new optical local area network that combines dense Wavelength Division Multiplexing (WDM) techniques and coherent transmission benefits is presented. A new multichannel protocol is specified based on Ethernet, using WDM to carry multiple channels on a single fiber. The protocol is simulated to evaluate the performance under congestion conditions and to compare it with other protocols having the same total capacity. Some suggestions are made for congestion control in high-capacity networks and different channel-jumping strategies are proposed. A network architecture is proposed with tunable transmitters and multichannel receivers, and with a common local oscillator.