What advantage does implementation of IEEE 802.1s MSTP offer over legacy STP or RSTP?
The 802.1D and 802.1w spanning tree protocols operate without regard to a network’s VLAN configuration, and maintain one common spanning tree throughout a bridged network. Thus, these protocols map one loop-free, logical topology on a given physical topology. This causes redundant links to be blocked; they are then available on a standby basis. With MSTP, each spanning tree instance can include one or more VLANs and applies a separate, per-instance forwarding topology. Thus, where a port belongs to multiple VLANs, it may be dynamically blocked in one spanning tree instance, but forwarding in another instance. This achieves load-balancing across the network while still providing fault tolerance through rapid, automatic reconfiguration if there is a failure in a network’s physical topology.
