Cisco Catalyst 2950 Command Reference Manual page 282

spanning-tree mst configuration
All VLANs that are not explicitly mapped to an MST instance are mapped to the common and internal
spanning tree (CIST) instance (instance 0) and cannot be unmapped from the CIST by using the no form
of the command.
For two or more switches to be in the same MST region, they must have the same VLAN mapping, the
same configuration revision number, and the same name.
Examples
This example shows how to enter MST configuration mode, map VLAN 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# 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
Revision
Instance
--------
0
1
-------------------------------
Switch(config-mst)# exit
Switch(config)#
This example shows how to add VLANs 1 to 100 to the ones already mapped (if any) to instance 2, to
move VLANs 40 to 60 that were previously mapped to instance 2 to the CIST instance, to add VLAN
10 to instance 10, and to remove all the VLANs mapped to instance 2 and map them to the CIST instance:
Switch(config-mst)# instance 2 vlan 1-100
Switch(config-mst)# no instance 2 vlan 40-60
Switch(config-mst)# instance 10 vlan 10
Switch(config-mst)# no instance 2
You can verify your settings by entering the show pending MST configuration command.
Related Commands Command
show spanning-tree
Catalyst 2950 Desktop Switch Command Reference
2-258
[region1]
1
Vlans Mapped
---------------------
1-9,21-4094
10-20
mst configuration
Description
Displays the MST region configuration.
Chapter 2 Cisco IOS Commands
78-11381-05