Reference Guide

Example
(Guard)
Dell#show spanning-tree 0 guard
Interface
Name Instance Sts Guard type
--------- -------- --------- ----------
Gi 0/1 0 INCON(Root) Rootguard
Gi 0/2 0 LIS Loopguard
Gi 0/3 0 EDS (Shut) Bpduguard
spanning-tree 0
Assigns a Layer 2 interface to STP instance 0 and configures a port cost or port priority, or enables loop
guard, root guard, or the Portfast feature on the interface.
Syntax
spanning-tree stp-id {cost cost | {loopguard | rootguard} |
portfast [bpduguard [shutdown-on-violation]] | priority
priority}
To disable Spanning Tree group on an interface, use the no spanning-tree
stp-id {cost cost | {loopguard | rootguard} | portfast
[bpduguard [shutdown-on-violation]] | priority priority}
command.
Parameters
stp-id Enter the STP instance ID. The range is 0.
cost cost Enter the keyword cost followed by a number as the cost.
The range is 1 to 65535. The defaults are:
• 100 Mb/s Ethernet interface = 19.
• 1-Gigabit Ethernet interface = 4.
• 10-Gigabit Ethernet interface = 2.
• Port Channel interface with 100 Mb/s Ethernet = 18.
• Port Channel interface with 1-Gigabit Ethernet = 3.
• Port Channel interface with 10-Gigabit Ethernet = 1.
loopguard (C-, S-, and E-Series TeraScale and S4810 only) Enter the
keyword loopguard to enable STP loop guard on a port or
port-channel interface.
rootguard (C-, S-, and E-Series TeraScale and S4810 only) Enter the
keyword rootguard to enable STP root guard on a port or
port-channel interface.
portfast
[bpduguard
[shutdown-on-
viol ation]]
Enter the keyword portfast to enable Portfast to move the
interface into Forwarding mode immediately after the root
fails.
Enter the optional keyword bpduguard to disable the port
when it receives a BPDU.
1900
Spanning Tree Protocol (STP)