Cisco Catalyst 2960 Series, Configuration Manual

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Purpose Command or Action
Enters the global configuration mode. configure terminal
Example:
Switch#
configure terminal
Step 2
Configures a switch as the secondary root switch. spanning-tree mst instance-id root secondary Step 3
Example:
Switch(config)# spanning-tree mst 0 root
secondary
• 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.
Returns to privileged EXEC mode. end
Example:
Switch(config)# end
Step 4
Related Topics
Specifying the MST Region Configuration and Enabling MSTP , on page 261
Configuring the Root Switch , on page 264
Configuring Port Priority
If a loop occurs, the MSTP uses the port priority when selecting an interface to put into the forwarding state.
You can assign higher priority values (lower numerical values) to interfaces that you want selected first and
lower priority values (higher numerical values) that you want selected last. If all interfaces have the same
priority value, the MSTP puts the interface with the lowest interface number in the forwarding state and blocks
the other interfaces.
If the switch is a member of a switch stack, you must use the spanning-tree mst [ instance-id ] cost cost
interface configuration command instead of the spanning-tree mst [ instance-id ] port-priority priority
interface configuration command to select a port to put in the forwarding state. Assign lower cost values
to ports that you want selected first and higher cost values to ports that you want selected last. For more
information, see the path costs topic listed under Related Topics.
Note
This procedure is optional.
Before You Begin
A multiple spanning tree (MST) must be specified and enabled on the switch. For instructions, see Related
Topics.
Consolidated Platform Configuration Guide, Cisco IOS Release 15.2(4)E (Catalyst 2960-X Switches)
266
How to Configure MSTP Features