Configuring The Port Cost - Cisco AP775A - Nexus Converged Network Switch 5010 Configuration Manual

Configuring MST
Step 2
Step 3
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.

Configuring the Port Cost

The MST path 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.
Note MST uses the long pathcost calculation method.
Procedure
Step 1
Step 2
Step 3
OL-16597-01
Command or Action
switch(config)# interface {{type
slot/port} | {port-channel
number}}
switch(config-if)# spanning-tree
mst instance-id port-priority
priority
Command or Action
switch# configure terminal
switch(config)# interface {{type
slot/port} | {port-channel
number}}
switch(config-if)# spanning-tree
mst instance-id cost [cost | auto]
Purpose
Specifies an interface to configure, and enters interface
configuration mode.
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.
Purpose
Enters configuration mode.
Specifies an interface to configure, and enters interface
configuration mode.
Configures the cost.
If a loop occurs, MST uses the path cost when selecting an
interface to place into the forwarding state. A lower path cost
represents higher-speed transmission as follows:
Cisco Nexus 5000 Series Switch CLI Software Configuration Guide
Configuring the Port Cost
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