A communication system includes communication protocols that allow a single network or multiple neighboring networks to increase resource sharing and reduce mutual interference and increase their overall throughput. Various protocols apply to homogenous networks in which all power line communication (PLC) devices of multiple networks are interoperable with respect to full power line communication in a common PHY and to heterogeneous networks having non-interoperable PLC networks which do not employ a common PHY. As to heterogeneous networks, a protocol herein enables coexistence via a special signaling scheme. In homogeneous networks, all nodes can communicate with each other using a common PHY, so that information about one PLC network can be transferred to another PLC network. In heterogeneous networks, not all PLC networks can exchange information using their own native PHY.