(Optional) Configuring the Root Device To configure the root device, perform this procedure: Before you begin • An MST must be specified and enabled on the device. . • You must also know the specified MST instance ID. Configuring Multiple Spanning-Tree Protocol (Optional) Configuring the Root Device Command or Action Purpose 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. Step 5 name name Example: Device(config-mst)# name region1 Specifies the configuration name.
The name string has a maximum length of 32 characters and is case sensitive. Step 6 revision version Example: Device(config-mst)# revision 1 Specifies the configuration revision number. The range is 0 to 65535. Step 7 show pending Example: Device(config-mst)# show pending Verifies your configuration by displaying the pending configuration. Step 8 exit Example: Device(config-mst)# exit Applies all changes, and returns to global configuration mode. Step 9 spanning-tree mode mst Example: Device(config)# spanning-tree mode mst Enables MSTP. RSTP is also enabled.
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. Step 10 end Example: Device(config)# end Returns to privileged EXEC mode. Configuring Multiple Spanning-Tree Protocol 17