A method to forward Ethernet frames associated with a service instance at a node, a "forwarding node", in a first network supporting an implementation of a protocol for creating logical loop-free topologies, wherein the service instance identifies a service through the first network, wherein Ethernet frames are forwarded in links associated with the service instance within the first network, wherein media access control, MAC, address registration with the first network complies with an implementation of multiple MAC registration protocol, MMRP, wherein nodes of the first network with MAC address interests issue MMRP protocol data units, PDUs, multiple MAC registration PDUs, MMRPDUs, that follow the service instance within the first network, the method comprising: receiving a first plurality of MMRPDUs at the forwarding node from links in the first network, receiving links, wherein each MMRPDU of the first plurality of MMRPDUs contains a first interested node list including one or more interested nodes identified by MAC addresses; identifying a service instance identifier, SID, for the service instance by extracting information from at least one of: each frame encapsulating an MMRPDU, encapsulating frame, and each MMRPDU itself; forming a first set of MAC addresses interested in the service instance, the first set of MAC addresses being associated with the forward node and the SID; sending a second plurality of MMRPDUs to links associated with the service instance, transmitting links, wherein the second plurality of MMRPDUs are encapsulated in a set of Ethernet frames identifying the service instance, wherein the set of encapsulated MMRPDUs contains a second set of MAC addresses, the second set of MAC addresses includes MAC addresses interested in the service instance not received from the transmitting link; and installing filtering at the forwarding node such that an Ethernet frame is forwarded at the receiving node to its destination if the Ethernet frame is destined to one or more interested nodes identified by the first set of MAC addresses. receiving a first plurality of MMRPDUs at the forwarding node from links in the first network, receiving links, wherein each MMRPDU of the first plurality of MMRPDUs contains a first interested node list including one or more interested nodes identified by MAC addresses; identifying a service instance identifier, SID, for the service instance by extracting information from at least one of: each frame encapsulating an MMRPDU, encapsulating frame, and each MMRPDU itself; each frame encapsulating an MMRPDU, encapsulating frame, and each MMRPDU itself; forming a first set of MAC addresses interested in the service instance, the first set of MAC addresses being associated with the forward node and the SID; sending a second plurality of MMRPDUs to links associated with the service instance, transmitting links, wherein the second plurality of MMRPDUs are encapsulated in a set of Ethernet frames identifying the service instance, wherein the set of encapsulated MMRPDUs contains a second set of MAC addresses, the second set of MAC addresses includes MAC addresses interested in the service instance not received from the transmitting link; and installing filtering at the forwarding node such that an Ethernet frame is forwarded at the receiving node to its destination if the Ethernet frame is destined to one or more interested nodes identified by the first set of MAC addresses.