Cisco Systems N3KC3048TP1GE Enabling Loop Guard Globally, loopguard default, Before You Begin

Configuring STP Extensions

Configuring STP Extensions

This example shows how to explicitly enable BPDU Filtering on the Ethernet spanning tree edge port 1/4:

switch# configure terminal

switch (config)# interface ethernet 1/4 switch(config-if)#spanning-tree bpdufilter enable

Enabling Loop Guard Globally

You can enable Loop Guard globally by default on all point-to-point spanning tree normal and network ports. Loop Guard does not run on edge ports.

Loop Guard provides additional security in the bridge network. Loop Guard prevents alternate or root ports from becoming the designated port because of a failure that could lead to a unidirectional link.

Note Entering the Loop Guard command for the specified interface overrides the global Loop Guard command.

Before You Begin

Ensure that STP is configured.

Ensure that you have spanning tree normal ports or have configured some network ports.

Procedure

	Command or Action	Purpose
Step 1	switch# configure terminal	Enters configuration mode.
Step 2	switch(config)# spanning-tree	Enables Loop Guard by default on all spanning tree
	loopguard default	normal and network ports. By default, global Loop
		Guard is disabled.

This example shows how to enable Loop Guard on all spanning tree normal or network ports:

switch# configure terminal

switch(config)# spanning-tree loopguard default

Enabling Loop Guard or Root Guard on Specified Interfaces

You can enable either Loop Guard or Root Guard on specified interfaces.

Enabling Root Guard on a port means that port cannot become a root port, and LoopGuard 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.

Note Entering the Loop Guard command for the specified interface overrides the global Loop Guard command.

	Cisco Nexus 3000 NX-OS Layer 2 Switching Configuration Guide, Release 5.0(3)U3(1)
124	OL-26590-01