Configuring The Switch Priority - Cisco Catalyst 3750-E Software Configuration Manual

Configuring MSTP Features
Beginning in privileged EXEC mode, follow these steps to configure the MSTP cost of an interface. This
procedure is optional.
Command
Step 1 configure terminal
Step 2
interface interface-id
Step 3
spanning-tree mst instance-id cost cost
Step 4 end
Step 5 show spanning-tree mst interface interface-id
or
show spanning-tree mst instance-id
Step 6
copy running-config startup-config
The show spanning-tree mst interface interface-id privileged EXEC command displays information
Note
only for ports that are in a link-up operative state. Otherwise, you can use the show running-config
privileged EXEC command to confirm the configuration.
To return the interface to its default setting, use the no spanning-tree mst instance-id cost interface
configuration command.

Configuring the Switch Priority

You can configure the switch priority and make it more likely that a standalone switch or a switch in the
stack will be chosen as the root switch.
Exercise care when using this command. For most situations, we recommend that you use the
Note
spanning-tree mst instance-id root primary and the spanning-tree mst instance-id root secondary
global configuration commands to modify the switch priority.
Catalyst 3750-E and 3560-E Switch Software Configuration Guide
19-22
Purpose
Enter global configuration mode.
Specify an interface to configure, and enter interface
configuration mode. Valid interfaces include physical ports and
port-channel logical interfaces. The port-channel range is 1 to 48.
Configure the cost.
If a loop occurs, the MSTP uses the path cost when selecting an
interface to place into the forwarding state. A lower path cost
represents higher-speed transmission.
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 cost, the range is 1 to 200000000; the default value is
•
derived from the media speed of the interface.
Return to privileged EXEC mode.
Verify your entries.
(Optional) Save your entries in the configuration file.
Chapter 19 Configuring MSTP
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