Apparatuses, methods, and computer-readable media support diagnosing a communications network using a network protocol that ensures a loop-free topology to prevent bridge loops. One of the network devices is identified as a selected device in a network ring, where the selected device interacts with the network ring through first and second ports. The values of some of the parameters of the selected device are modified to be distinguishable from that of any network device in the ring, and diagnostics about the functioning of the network protocol are then performed to obtain state information about the first and second ports. When one of the ports is determined to be in the blocking state, network redundancy for the network ring is verified. However, when neither of the ports is not in the blocking state, a redundancy problem may be detected.