Shortest Path Bridging (SPB) enables a next generation control plane for PBB based on IS-IS that adds the stability and efficiency of link state to unicast and multicast services. Specifically this is an implementation of SPBM (SPB MAC mode). Current SR OS PBB B-VPLS offers point-to-point and multipoint to multipoint services with large scale. PBB B-VPLS is deployed in both Ethernet and MPLS networks supporting Ethernet VLL and VPLS services. SPB removes the flooding and learning mode from the PBB Backbone network and replaces MMRP for ISID Group MAC Registration providing flood containment. SR OS SPB provides true shortest path forwarding for unicast and efficient forwarding on a single tree for multicast. It supports selection of shortest path equal cost tie-breaking algorithms to enable diverse forwarding in an SPB network.