Cisco Systems N3KC3064TFAL3 Configuring the Port Priority, Procedure, Command or Action, Purpose

Configuring Multiple Spanning Tree

Configuring the Port Priority

	Command or Action	Purpose
Step 3	switch(config)# no spanning-tree	(Optional)
	mst instance-id root	Returns the switch priority, diameter, and hello-time to default
		values.

This example shows how to configure the switch as the secondary root switch for MSTI 5:

switch# configure terminal

switch(config)# spanning-tree mst 5 root secondary

Configuring the Port Priority

If a loop occurs, MST uses the port priority when selecting an interface to put into the forwarding state. You can assign lower priority values to interfaces that you want selected first and higher priority values to the interface that you want selected last. If all interfaces have the same priority value, MST puts the interface with the lowest interface number in the forwarding state and blocks the other interfaces.

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-channel	configuration mode.
	number}}

Step 3 switch(config-if)# spanning-tree mst instance-idport-prioritypriority

Configures the port priority as follows:

•For instance-id, you can specify a single MSTI, a range of MSTIs separated by a hyphen, or a series of MSTIs separated by a comma. The range is from 1 to 4094.

•For priority, the range is 0 to 224 in increments of 32. The default is 128. A lower number indicates a higher priority.

The priority values are 0, 32, 64, 96, 128, 160, 192, and 224. The system rejects all other values.

This example shows how to set the MST interface port priority for MSTI 3 on Ethernet port 3/1 to 64:

switch# configure terminal switch(config)# interface ethernet 3/1

switch(config-if)#spanning-tree mst 3 port-priority 64

You can only apply this command to a physical Ethernet interface.

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

OL-26590-01 105