Configuring The Port Cost - Cisco nexus 5000 series Configuration Manual

Configuring Multiple Spanning Tree
Command or Action
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.
MST uses the long path-cost calculation method.
Note
SUMMARY STEPS
1. switch# configure terminal
2. switch(config)# interface {{type slot/port} | {port-channel number}}
3. switch(config-if)# spanning-tree mst instance-id cost [cost | auto]
DETAILED STEPS
Command or Action
Step 1
switch# configure terminal
Step 2
switch(config)# interface {{type
slot/port} | {port-channel number}}
Step 3
switch(config-if)# spanning-tree mst
instance-id cost [cost | auto]
OL-25842-01
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 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 global configuration mode.
Specifies an interface to configure, and enters interface configuration mode.
Configures the cost.
Cisco Nexus 5000 Series NX-OS Layer 2 Switching Configuration Guide, Release 5.1(3)N1(1)
Configuring the Port Cost
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