Specifications

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Cisco MWR 2941 Mobile Wireless Edge Router Release 3.5 Software Configuration Guide, Cisco IOS Release 15.1(3)MR
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Chapter 10 Configuring MSTP
Configuring MSTP Features
Beginning in privileged EXEC mode, follow these steps to configure the MSTP port priority of an
interface. This procedure is optional.
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 MSTP path cost default value is derived from the media speed of an STP port. If a loop occurs, the
MSTP uses cost when selecting an interface to put in the forwarding state. You can assign lower cost
values to STP ports that you want selected first and higher cost values that you want selected last. If all
interfaces have the same cost value, the MSTP puts the interface with the lowest interface number in the
forwarding state and blocks the other interfaces.
Beginning in privileged EXEC mode, follow these steps to configure the MSTP cost of an interface. This
procedure is optional.
Command Purpose
Step 1
configure terminal Enter global configuration mode.
Step 2
interface interface-id Specify an interface to configure, and enter interface
configuration mode.
Valid interfaces include physical NNIs or ENIs with spanning
tree enabled, VLANs, and NNIs. The VLAN ID range is 1 to
4094. The port-channel range is 1 to 48.
Note If the interface is a VLAN, only ports with spanning tree
enabled in the VLAN will run spanning tree.
Step 3
spanning-tree mst instance-id port-priority
priority
Configure 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.
Step 4
end Return to privileged EXEC mode.
Step 5
show spanning-tree mst interface interface-id
or
show spanning-tree mst instance-id
Verify your entries.
Step 6
copy running-config startup-config (Optional) Save your entries in the configuration file.