Cisco Nexus 5000 Series Switch CLI Software Configuration Guide, NX-OS 4.0(1a)N1 (OL-16597-01, January 2009)

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Cisco Nexus 5000 Series Switch CLI Software Configuration Guide
OL-16597-01
Chapter 9 Configuring MST
Configuring MST
To enable a secondary root bridge, perform this task:
This example shows how to configure the switch as the secondary root switch for MSTI 5:
switch# configure terminal
switch(config)# spanning-tree mst 5 root secondary
To disable the secondary root bridge configuration, perform this task:
Configuring the Port Priority
If a loop occurs, MST uses the port priority when selecting an interface to put into the forwarding state.
You can assign lower priority values to interfaces that you want selected first and higher priority values
to the interface that you want selected last. If all interfaces have the same priority value, MST puts the
interface with the lowest interface number in the forwarding state and blocks the other interfaces.
To configure the port priority, perform this task:
Command Purpose
Step 1
switch# configure terminal
Enters configuration mode.
Step 2
switch(config)# spanning-tree mst
instance-id root {primary | secondary}
[diameter dia [hello-time hello-time]]
Configures a switch as the secondary root bridge as
follows:
• 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 from 1 to 4094.
• For diameter net-diameter, specify the maximum
number of hops between any two end stations.
The default is 7. This keyword is available only
for MST instance 0.
• For hello-time seconds, specify the interval in
seconds between the generation of configuration
messages by the root bridge. The range is from 1
to 10 seconds; the default is 2 seconds.
Command Purpose
switch(config)# no spanning-tree mst
instance-id root
Returns the switch priority, diameter, and hello-time
to default values.
Command Purpose
Step 1
switch# configure terminal
Enters configuration mode.