Configuring The Mst Port Cost - Cisco Nexus 9000 Series Configuration Manual

Configuring MST Using Cisco NX-OS
Step 4
Step 5
Step 6
This example shows how to set the MST interface port priority for MSTI 3 on Ethernet port 3/1 to 64:
switch# config t
switch(config)# interface ethernet 3/1
switch(config-if)# spanning-tree mst 3 port-priority 64
switch(config-if)# exit
switch(config)#

Configuring the MST Port Cost

The MST port cost default value is derived from the media speed of an interface. If a loop occurs, MST uses
the cost when selecting an interface to put in the forwarding state. You can assign lower cost values to interfaces
that you want selected first and higher cost to interfaces values that you want selected last. If all interfaces
have the same cost value, MST puts the interface with the lowest interface number in the forwarding state
and blocks the other interfaces.
MST uses the long path-cost calculation method.
Note
Command or Action
Example:
switch(config-if)# spanning-tree mst
3 port-priority 64
exit
Example:
switch(config-if)# exit
switch(config)#
show spanning-tree mst
Example:
switch# show spanning-tree mst
copy running-config startup-config
Example:
switch(config)# copy running-config
startup-config
Cisco Nexus 9000 Series NX-OS Layer 2 Switching Configuration Guide, Release 7.x
Configuring the MST Port Cost
Purpose
• 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 from 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.
Exits interface mode.
(Optional)
Displays the MST configuration.
(Optional)
Copies the running configuration to the startup
configuration.
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