28.3.1 Load Balancing with PVST+

When Single Spanning Tree is used in a network that has redundant paths between switches, such as Switch A and Switch B in the figure below, access from each terminal to the server is concentrated on port 1 between Switches A and B. In this case, PVST+ can be used to set up multiple VLANs that have different topologies in order to create redundant paths, which would allow the load to be distributed. The figure below shows an example of load balancing by port priority.

In this example, the port priority for VLAN 100 is set higher for port 1/0/1 than port 1/0/2, whereas the port priority for VLAN 200 is set higher for port 1/0/2 than port 1/0/1, allowing access from each terminal to the server to be load-balanced for each VLAN.

Figure 28-5 Load balancing by PVST+