A multi-chip module (MCM) may include a substrate, and first and second physical-layer (PHY) chips mounted on the substrate. In some implementations, the first PHY chip includes a multiplexer and a PHY circuit. The multiplexer is configured to receive a multiplexed data stream from a media access control (MAC) device, to demultiplex the multiplexed data stream into first and second data streams, to output the first data stream to the PHY circuit, and to output the second data stream to the second PHY chip. In some implementations, the first PHY includes a router and a PHY circuit. The router is configured to receive a plurality of data packets from a MAC device, to route one or more of the data packets having a first address to the PHY circuit, and to route one or more of the data packets having a second address to the second PHY chip.