Reference Guide

878 | Spanning Tree Protocol (STP)
www.dell.com | support.dell.com
Confirm that a port is participating in Spanning Tree using the show spanning-tree 0 brief command from
EXEC privilege mode.
Figure 45-6. show spanning-tree brief Command Example
Adding an Interface to the Spanning Tree Group
To add a Layer 2 interface to the Spanning Tree topology:
Removing an Interface from the Spanning Tree Group
To remove a Layer 2 interface from the Spanning Tree topology:
Task Command Syntax Command Mode
Enable Spanning Tree on a Layer 2 interface. spanning-tree 0 INTERFACE
Task Command Syntax Command Mode
Disable Spanning Tree on a Layer 2 interface. no spanning-tree 0 INTERFACE
In FTOS versions prior to 7.6.1.0, the command no spanning tree disables Spanning Tree on the interface,
however, BPDUs are still forwarded to the RPM, where they are dropped. Beginning in FTOS version 7.6.1.0,
the command no spanning tree disables Spanning Tree on the interface, and incoming BPDUs are dropped at
the line card instead of at the RPM, which frees processing resources. This behavior is called Layer 2 BPDU
filtering and is available for STP, RSTP, PVST+, and MSTP.
FTOS#show spanning-tree 0 brief
Executing IEEE compatible Spanning Tree Protocol
Root ID Priority 32768, Address 0001.e80d.2462
We are the root of the spanning tree
Root Bridge hello time 2, max age 20, forward delay 15
Bridge ID Priority 32768, Address 0001.e80d.2462
Configured hello time 2, max age 20, forward delay 15
Interface Designated
Name PortID Prio Cost Sts Cost Bridge ID PortID
-------------- ------ ---- ---- --- ----- ----------------- ------
Gi 1/1 8.496 8 4 DIS 0 32768 0001.e80d.2462 8.496
Gi 1/2 8.497 8 4 DIS 0 32768 0001.e80d.2462 8.497
Gi 1/3 8.513 8 4 FWD 0 32768 0001.e80d.2462 8.513
Gi 1/4 8.514 8 4 FWD 0 32768 0001.e80d.2462 8.514
FTOS#