Communications system including symmetric bus bridge and method used therewith

A method of (and system for) of transporting a sideband signal through a physical layer of an extended bridge, includes on a first node of the extended bridge, providing an interface to a sideband component coupled to a side of the extended bridge, encoding a first data stream being output from the sideband component with a unique header to identify the data output from the sideband component, and multiplexing the first data stream from the sideband component with a second data stream from a principal signal port, and outputting the multiplexed first and second data streams to another node of the extended bridge.