By default, Dell SmartFabric OS10 uses Rapid per-VLAN Spanning Tree Plus (RPVST+) across all switching platforms. Dell SmartFabric OS10 also supports RSTP and MST.
Use caution when connecting an RPVST+ to an existing RSTP environment. RPVST+ creates a single topology per VLAN with the default VLAN, typically VLAN 1, for the Common Spanning Tree (CST) with RSTP.
For non-native VLANs, the upstream, RSTP-enabled switch with the associated VLAN tags and forwards all Bridge Protocol Data Unit (BPDU) traffic. These BPDUs use a protocol-specific multicast address. Any other RPVST+ tree attached to the RSTP tree might process these packets accordingly, leading to the potential of unexpected trees.
In the example below, RSTP is enabled globally. MST configuration is similar.
OS10(config)# spanning-tree mode rstp
OS10(config)# end
OS10#show spanning-tree brief
Spanning tree enabled protocol rstp with force-version rstp
Executing IEEE compatible Spanning Tree Protocol
Root ID Priority 0, Address 4c76.25e8.f2c0
Root Bridge hello time 2, max age 20, forward delay 15
Bridge ID Priority 32768, Address 2004.0f00.cd1e
Configured hello time 2, max age 20, forward delay 15
Flush Interval 200 centi-sec, Flush Invocations 95
Flush Indication threshold 0 (MAC flush optimization is disabled)