MISTP (802.1s) is an IEEE standard which allows several VLANs to be mapped to a reduced number of spanning-tree instances. This is possible since most networks do not need more than a few logical topologies. Each instance handles multiple VLANs that have the same Layer 2 topology.
(All Spanning Tree Protocol Configuration Examples and TechNotes)
(All Spanning Tree Protocol Maintain and Operate TechNotes)
(All Spanning Tree Protocol Configuration Example and TechNotes)