Cisco Nexus 7000 Series Configuration Manual page 214

Enabling Loop Guard or Root Guard on Specified Interfaces
Enabling Root Guard on a port means that port cannot become a root port, and Loop Guard prevents alternate
or root ports from becoming the designated port because of a failure that could lead to a unidirectional link.
Both Loop Guard and Root Guard enabled on an interface apply to all VLANs to which that interface belongs.
Entering the Loop Guard command for the specified interface overrides the global Loop Guard command.
Note
Before You Begin
• Ensure that you are in the correct VDC (or enter the switchto vdc command).
• Ensure that STP is configured.
• Ensure that you are configuring Loop Guard on spanning tree normal or network ports.
SUMMARY STEPS
1. switch# config t
2. switch(config)# interface type slot/port
3. switch(config-if)# spanning-tree guard {loop | root | none}
4. switch(config-if)# exit
5. switch(config)# interface type slot/port
6. switch(config-if)# spanning-tree guard {loop | root | none}
7. switch(config-if)# exit
8. (Optional) switch# show spanning-tree interface type slot/port detail
9. (Optional) switch(config)# copy running-config startup-config
DETAILED STEPS
Command or Action
Step 1
switch# config t
Step 2
switch(config)# interface type slot/port
Step 3 switch(config-if)# spanning-tree guard
{loop | root | none}
Step 4 switch(config-if)# exit
Step 5 switch(config)# interface type slot/port
Cisco Nexus 7000 Series NX-OS Layer 2 Switching Configuration Guide, Release 5.x
198
Configuring STP Extensions Using Cisco NX-OS
Purpose
Enters global configuration mode.
Specifies the interface to configure and enters interface configuration
mode.
Enables or disables either Loop Guard or Root Guard for the specified
interface. By default, Root Guard is disabled by default, and Loop
Guard on specified ports is also disabled.
Loop Guard runs only on spanning tree normal and network
Note
interfaces. This example shows Loop Guard is enabled on
the specified interface.
Exits interface configuration mode.
Specifies the interface to configure and enters interface configuration
mode.