Multiple Spanning Tree Instances

MSTIs control the topology inside an MSTP (Multiple Spanning Tree Protocol) region. An MSTI is a spanning tree domain that operates within a region and is bounded by that region; and MSTI does not exchange BPDU (Bridge Protocol Data Unit)s or send notifications to other regions. You can map multiple VLAN (Virtual LAN)s to an MSTI; however, each VLAN can belong to only one MSTI. You can configure up to 64 MSTIs in an MSTP region.