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Catalyst 2960 Switch SoftwareConfiguration Guide
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Chapter16 Configuring MSTP
Configuring MSTP Features
Specifying the MST Region Configuration and Enabling MSTP
For two or more switches to be in the same MST region, they must have the same VLAN-to-instance
mapping, the same configuration revision number, and the same name.
A region can have one member or multiple members with the sam e MST configuration; each member
must be capable of processing RSTP BPDUs. There is no limit t o the number of MST regions in a
network, but each region can only support up to 16 spanning-tree i nstances. You can assign a VLAN to
only one spanning-tree instance at a time.
Beginning in privileged EXEC mode, follow these steps to specify the MST region configuration and
enable MSTP. This procedure is required.
Command Purpose
Step1 configure terminal Enter global configuration mode.
Step2 spanning-tree mst configuration Enter MST configuration mode.
Step3 instance instance-id vlan vlan-range Map VLANs to an MST instance.
•For instance-id, the range is 0 to 15.
•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.