How to Configure Multiple Spanning Tree Protocol and Parameters The following sections provide information about configuring MSTP and MSTP parameters: Specifying the Multiple Spanning Tree Region Configuration and Enabling Multiple Spanning Tree Protocol 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 same MST configuration; each member must be capable of processing RSTP BPDUs. There is no limit to the number of MST regions in a network, but each region can only support up to 65 spanning-tree instances.
You can assign a VLAN to only one spanning-tree instance at a time. Procedure Configuring Multiple Spanning-Tree Protocol How to Configure Multiple Spanning Tree Protocol and Parameters Command or Action Purpose Step 1 enable Example: Device> enable Enables privileged EXEC mode. Enter your password if prompted. Step 2 configure terminal Example: Device# configure terminal Enters global configuration mode. Step 3 spanning-tree mst configuration Example: Device(config)# spanning-tree mst configuration Enters MST configuration mode. Step 4 instance instance-id vlan vlan-range Example: Device(config-mst)# instance 1 vlan 10-20 Maps 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. Configuring Multiple Spanning-Tree Protocol 16