Dell C1048P Port Extender Networking Configuration Guide for the C9000 Series - Page 1082

The range is from 0 to 15. The default is 8. To view the current values for interface parameters, use the show spanning-tree 0 command from EXEC privilege mode. Refer to the second example in Enabling Spanning Tree Protocol Globally. Enabling PortFast The PortFast feature enables interfaces to begin forwarding traffic approximately 30 seconds sooner. Interfaces forward frames by default until they receive a BPDU that indicates that they should behave otherwise; they do not go through the Learning and Listening states. The bpduguard shutdown-onviolation option causes the interface hardware to be shut down when it receives a BPDU. When you only implement bpduguard, although the interface is placed in an Error Disabled state when receiving the BPDU, the physical interface remains up and spanning-tree drops packets in the hardware after a BPDU violation. BPDUs are dropped in the software after receiving the BPDU violation. CAUTION: Enable PortFast only on links connecting to an end station. PortFast can cause loops if it is enabled on an interface connected to a network. To enable PortFast on an interface, use the following command. • Enable PortFast on an interface. INTERFACE mode spanning-tree stp-id portfast [bpduguard | [shutdown-on-violation]] Example of Verifying PortFast is Enabled on an Interface To verify that PortFast is enabled on a port, use the show spanning-tree command from EXEC Privilege mode or the show config command from INTERFACE mode. Dell Networking recommends using the show config command. Dell#(conf-if-te-1/1)#show conf ! interface TenGigabitEthernet 1/1 no ip address switchport spanning-tree 0 portfast no shutdown Dell#(conf-if-te-1/1)# Spanning Tree Protocol (STP) 1082