MN700004 Rev 01 11012. Spanning Tree Protocol (STP)IntroductionThe Spanning Tree Algorithm and Protocol are part of the ANSI/IEEE Std 802.1D MACBridges specifications sponsored by the LAN/MAN Standards Committee of the IEEEComputer Society.STP (Spanning-Tree Protocol) provides fault tolerance on networks, by allowing you toimplement parallel paths for network traffic. The algorithm creates a spanning tree (a loop-free subset of the network topology), that enables a learning bridge to dynamically workaround loops in a network topology. STP allows you to implement redundant paths that areenabled only when the main paths fail.STP configuration is disabled by default.Configuring and Debugging STPYou can use STP configuration commands per switch or per interface. To enable per-switchSTP configuration commands, you must enter Protocol Configuration mode, by using thefollowing command in global Configuration mode:device-name(config)#protocoldevice-name(cfg protocol)#The (cfg protocol)# prompt-line indicates Protocol Configuration mode.To access the STP interface configuration commands, use the following command in globalConfiguration mode:device-name(config)#interface UU/SS/PPdevice-name(config-if UU/SS/PP)#Argument DescriptionUU/SS/PP Unit, slot and port number of an interface (i.e. – 1/1/8).The (config-if UU/SS/PP)# prompt-line indicates interface UU/SS/PP Configurationmode.Table 12-1 summarizes the STP commands available in Protocol Configuration mode.Table 12-2 summarizes the STP commands available in interface configuration mode.Table 12-3 summarizes the STP debug commands.
