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Catalyst 3750 SwitchSoftware Configuration Guide
OL-8550-09
Chapter19 Configuring MSTP
Configuring MSTP Features
To return to the default MST region configuration, use the no spanning-tree mst configuration global
configuration command. To return to the default VLAN-to-instance map, use the no instance instance-id
[vlan vlan-range] MST configuration command. To return to the default name, use the no name MST
configuration command. To return to the default revision number, use the no revision MST configuration
command. To re-enable PVST+, use the no spanning-tree mode or the spanning-tree mode pvst global
configuration command.
This example shows how to enter MST configuration mode, map VLANs 10 to 20 to MST instance 1,
name the region region1, set the configuration revision to 1, display the pending configuration, apply the
changes, and return to global configuration mode:
Switch(config)# spanning-tree mst configuration
Switch(config-mst)# instance 1 vlan 10-20
Switch(config-mst)# name region1
Switch(config-mst)# revision 1
Switch(config-mst)# show pending
Pending MST configuration
Name [region1]
Revision 1
Step3 instance instance-id vlan vlan-range Map VLANs to an MST instance.
For instance-id, the range is 0 to 4094.
For vlan vlan-range, the range is 1 to 4094.
When you map VLANs to an MST instance, the mapping is
incremental, and the VLANs specified in the command are added to
or removed from the VLANs that were previously mapped.
To specify a VLAN range, use a hyphen; for example, instance 1 vlan
1-63 maps VLANs 1 through 63 to MST instance 1.
To specify a VLAN series, use a comma; for example, instance 1 vlan 10,
20, 30 maps VLANs 10, 20, and 30 to MST instance 1.
Step4 name name Specify the configuration name. The name string has a maximum length
of 32 characters and is case sensitive.
Step5 revision version Specify the configuration revision number. The range is 0 to 65535.
Step6 show pending Verify your configuration by displaying the pending configuration.
Step7 exit Apply all changes, and return to global configuration mode.
Step8 spanning-tree mode mst Enable MSTP. RSTP is also enabled.
Caution Changing spanning-tree modes can disrupt traffic because all
spanning-tree instances are stopped for the previous mode and
restarted in the new mode.
You cannot run both MSTP and PVST+ or both MSTP and rapid PVST+
at the same time.
Step9 end Return to privileged EXEC mode.
Step10 show running-config Verify your entries.
Step11 copy running-config startup-config (Optional) Save your entries in the configuration file.
Command Purpose