28.7.2 Network Design for Multiple Spanning Tree

(1) Load Balancing Configuration per MST Instance

Multiple Spanning Tree allows load balancing to be performed for each MST instance. The figure below shows an example configuration for load balancing. In this example, VLANs 10 and 20 are set for MST instance 1, VLANs 30 and 40 are set for MST instance 2, for load balancing in two parts. As shown in this example, Multiple Spanning Tree can enable load balancing by managing four VLANs with just two trees.

Figure 28-11: Load balancing configuration for Multiple Spanning Tree

(2) Designing Networking with MST regions

Network design becomes more complicated as network configurations grow larger, but MST regions can be used to divide them into smaller configurations to simplify network design, such as by implementing load balancing for each MST region.

The figure below shows an example network design based on MST regions. In this example, Switches A, B, and C are set for MST region 1, Switches D, E, and F are set for MST region 2, and Switches G, H, and I are set for MST region 3, dividing the network into three MST regions.

Figure 28-12 Network configuration based on the MST region