Cisco Systems N3KC3048TP1GE, N3KC3064TFAL3 manual Configuring Pvst Simulation Per Port

Configuring Multiple Spanning Tree

Configuring PVST Simulation Per Port

Procedure

	Command or Action	Purpose
Step 1	switch# configure terminal	Enters configuration mode.
Step 2	switch(config)# no spanning-tree	Disables all interfaces on the switch from automatically
	mst simulate pvst global	interoperating with connected switch that is running in Rapid
		PVST+ mode. The default for this is enabled; that is, by
		default, all interfaces on the switch operate seamlessly
		between Rapid PVST+ and MST.

This example shows how to prevent the switch from automatically interoperating with a connecting switch that is running Rapid PVST+:

switch# configure terminal

switch(config)# no spanning-tree mst simulate pvst global

Configuring PVST Simulation Per Port

MST interoperates seamlessly with Rapid PVST+. However, to prevent an accidental connection to a switch that does not run MST as the default STP mode, you may want to disable this automatic feature. If you disable PVST simulation, the MST-enabled port moves to the blocking state once it detects it is connected to a Rapid PVST+-enabled port. This port remains in the inconsistent state until the port stops receiving BPDUs, and then the port resumes the normal STP transition process.

You can block this automatic feature either globally or per port.

Procedure

	Command or Action	Purpose
Step 1	switch# configure terminal	Enters configuration mode.
Step 2	switch(config)# interface {{type	Specifies an interface to configure, and enters interface
	slot/port} {port-channelnumber}}	configuration mode.
Step 3	switch(config-if)# spanning-tree mst	Disables specified interfaces from automatically
	simulate pvst disable	interoperating with connected switch that is running in
		Rapid PVST+ mode.
		By default, all interfaces on the switch operate
		seamlessly between Rapid PVST+ and MST.
Step 4	switch(config-if)# spanning-tree mst	Re-enables seamless operation between MST and Rapid
	simulate pvst	PVST+ on specified interfaces.
Step 5	switch(config-if)# no spanning-tree	Sets the interface to the switch-wide MST and Rapid
	mst simulate pvst	PVST+ interoperation that you configured using the
		spanning-tree mst simulate pvst global command.

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