Netgear XCM8810 Chassis User Manual - Page 553

NETGEAR 8800 User Manual change, that bridge starts the topology change timer, sets the topology change flag on its BPDUs, floods all of the forwarding ports in the network (including the root ports), and flushes the learned MAC address entries. Rapid Reconvergence This section describes the RSTP rapid behavior following a topology change. In this example, the bridge priorities are assigned based on the order of their alphabetical letters; bridge A has a higher priority than bridge F. Suppose we have a network, as shown in Figure 42, with six bridges (bridge A through bridge F) where the following is true: • Bridge A is the root bridge. • Bridge D contains an alternate port in the blocking state. • All other ports in the network are in the forwarding state. A B C A , 0 A , 1 A , 2 F E D A , 1 A , 2 A , 3 Designated Root Blocked port port port EX_055a Figure 42. Initial Network Configuration The network reconverges in the following way: 1. If the link between bridge A and bridge F goes down, bridge F detects the root port is down. At this point, bridge F: • Immediately disables that port from the STP. • Performs a configuration update. As shown in Figure 43, after the configuration update, bridge F: • Considers itself the new root bridge. • Sends a BPDU message on its designated port to bridge E. Chapter 18. STP | 553