Abstract: Resources for computing an active network topology in a system having a plurality of ports coupled to respective local area networks include a protocol entity coupled to the plurality of ports which communicates with protocol entities in other systems on the networks to establish the active network topology. Port state logic, coupled with the protocol entity and the plurality of ports establishes active network states for the plurality of ports. The active network states include a first network state for forwarding data and a second network state for blocking data, wherein a transition from a first network state to a second network state is executed after receiving information from the protocol entity indicating a change to the second network state.