Dell MX5108n OS10 Enterprise Edition User Guide for PowerEdge MX IO Modules Re - Page 229

By default, each VLAN instance is assigned default bridge priority 32768. For example, all three instances have the same forwarding topology. Traffic load balancing is not achievable with this kind of priority assignment. You must assign each instance a different priority to achieve load balancing, as shown in Load Balancing with RPVST+. Load balance and root selection All VLANs use the same forwarding topology - R2 is elected as the root and all 10G Ethernet ports have the same cost. RPVST+ changes the bridge priority of each bridge so that a different forwarding topology generates for each VLAN. To achieve RPVST+ load balancing, assign a different priority on each bridge. Enable RPVST+ By default, RPVST+ is enabled and creates an instance only after you add the first member port to a VLAN. Port-channel or physical interfaces must be a member of a VLAN to participate in RPVST+. Add all physical and port-channel interfaces to the default VLAN (VLAN1). • Enable the Rapid-PVST+ mode in CONFIGURATION mode. spanning-tree mode rapid-pvst Configure RPVST+ OS10(config)# spanning-tree mode rapid-pvst View RPVST+ configuration OS10# show spanning-tree active Spanning tree enabled protocol rapid-pvst with force-version rstp VLAN 1 Executing IEEE compatible Spanning Tree Protocol Root ID Priority 32768, Address 3417.4455.667f Root Bridge hello time 2, max age 20, forward delay 15 Bridge ID Priority 32769, Address 90b1.1cf4.a523 Configured hello time 2, max age 20, forward delay 15 Interface Designated Name PortID Prio Cost Sts Cost Bridge ID PortID Layer 2 229