3Com 3C16476A User Guide - Page 48

48 CHAPTER 4: CONFIGURING THE SWITCH the Root Bridge generates BPDUs (Bridge Protocol Data Units) on all ports at a regular interval known as the Hello Time. All other spanning tree-compliant devices on the network have a designated Root Port. This is the Port nearest the Root Bridge and it is used for receiving the BPDUs initiated by the Root Bridge. If a bridge does not get a Hello BPDU after a predetermined interval, the bridge assumes that the link to the Root Bridge is down. This bridge will then initiate negotiations with other bridges to reconfigure the network to re-establish a valid network topology. After all the bridges on the network have determined the configuration of their ports, each bridge only forwards traffic between the Root Port and the ports that are the Designated Bridge Ports for each network segment. All other ports are blocked, which means that they are prevented from forwarding traffic. Three tabs are available on the Spanning Tree per Port page: ■ Summary ■ Detail ■ Setup Summary Use the Summary tab to display Status, Edged Port, Link Type, Path Cost, State, or Port Priority for all the ports. Figure 45 Spanning Tree Summary Screen Detail Use the Detail tab to display detailed spanning tree information for a port.