748 Configuring the Spanning Tree Protocol
Configuring STP Interface Settings

Beginning in Privileged EXEC mode, use the following commands to

configure the STP settings for a specific interface.

spanning-tree tcnguard Prevent the port from propagating topology change
notifications.
CTRL + Z Exit to Privileged EXEC mode.
show spanning-tree
summary
View various spanning tree settings and parameters for the
switch.
Command Purpose
configure Enter global configuration mode.
interface
interface
Enter interface configuration mode for the specified
interface. The
interface
variable includes the interface type
and number, for example tengigabitethernet 1/0/3 or port-
channel 4.
You can also specify a range of interfaces with the interface
range command, for example, interface range
tengigabitethernet 1/0/8-12 configures interfaces 8, 9, 10,
11, and 12. The range keyword is also valid for LAGs (port-
channels).
spanning-tree disable Disable spanning tree on the port.
spanning-tree port-
priority
priority
Specify the priority of the port. (Range: 0–240).
The priority value is used to determine which ports are put
in the forwarding state and which ports are put in the
blocking state. A port with a lower priority value is more
likely to be put into a forwarding state.
spanning-tree cost
cost
Specify the spanning tree path cost for the port. (Range:
0–200,000,000). The default cost is 0, which signifies that
the cost is automatically calculated based on port speed.
CTRL + Z Exit to Privileged EXEC mode.
show spanning-tree
interface
View spanning tree configuration information for the
specified port or LAG (port-channel).
Command Purpose