Configuring Path Cost - Cisco WS-SUP32-GE-3B - Supervisor Engine 32 Software Configuration Manual

Chapter 17 Configuring STP and MST
Command
Step 3
Router(config-if)# spanning-tree mst instance_id
port-priority priority
Step 4
Router(config-if)# end
Step 5
Router# show spanning-tree mst interface
interface_id
or
Router# show spanning-tree mst instance_id
Step 6
Router# copy running-config startup-config
Note The show spanning-tree mst interface interface_id privileged EXEC command displays information
only if the port is in a link-up operative state. Otherwise, you can use the show running-config interface
privileged EXEC command to confirm the configuration.
To return the interface to its default setting, use the no spanning-tree mst instance_id port-priority
interface configuration command.

Configuring Path Cost

The MST path cost default value is derived from the media speed of an interface. If a loop occurs, MST
uses 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 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.
To configure the MST cost of an interface, perform this task:
Command
Step 1
Router# configure terminal
Step 2
Router(config)# interface
{{gigabitethernet 1/port} | {port-channel
number}}
OL-11439-03
Catalyst Supervisor Engine 32 PISA Cisco IOS Software Configuration Guide, Release 12.2ZY
Purpose
Configures the port priority.
• For instance_id, you can specify a single instance, a
range of instances separated by a hyphen, or a series
of instances separated by a comma. The range is 0 to
4094.
For priority, the range is 0 to 240 in increments of 16.
•
The default is 128. The lower the number, the higher
the priority.
The priority values are 0, 16, 32, 48, 64, 80, 96, 112,
128, 144, 160, 176, 192, 208, 224, and 240. All other
values are rejected.
Returns to privileged EXEC mode.
Verifies your entries.
(Optional) Saves your entries in the configuration file.
Purpose
Enters global configuration mode.
(Optional) Specifies an interface to configure, and enters
interface configuration mode.
Configuring MST
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