650 Configuring the Spanning Tree ProtocolConfiguring Optional STP FeaturesBeginning in Privileged EXEC mode, use the following commands toconfigure the optional STP features on the switch or on specific interfaces.Command Purposeconfigure Enter global configuration mode.spanning-tree bpdufloodingAllow the flooding of BPDUs received on non-spanning-tree ports to all other non-spanning-tree ports.spanning-tree portfast Enable PortFast on all switch ports.spanning-tree portfastbpdufilter defaultPrevent ports configured in PortFast mode from sendingBPDUs.spanning-tree loopguarddefaultEnable loop guard on all ports.spanning-tree bpdu-protectionEnable BPDU protection on the switch.interfaceinterface Enter interface configuration mode for the specifiedinterface. Theinterface variable includes the interface typeand number, for example gigabitethernet 1/0/3 or port-channel 4.You can also specify a range of interfaces with the interfacerange command, for example, interface rangegigabitethernet 1/0/8-12 configures interfaces 8, 9, 10, 11,and 12. The range keyword is also valid for LAGs (portchannels).spanning-tree auto-portfastSet the port to auto portfast mode. This enables the portto become a portfast port if it does not see any BPDUs for3 seconds.spanning-tree guard{root | loop | none}Enable loop guard or root guard (or disable both) on theinterface.spanning-tree tcnguard Prevent the port from propagating topology changenotifications.CTRL + Z Exit to Privileged EXEC mode.show spanning-treesummaryView various spanning tree settings and parameters for theswitch.
