Supermicro SSE-F3548S/SSE-F3548SR Configuration User’s Guide
When a switch starts spanning tree it sends out BPDUs with its bridge ID as the root bridge ID. When a
switch receives the BDPUs, it compares the received root bridge ID with its own bridge ID. If the received
root bridge ID is lower than its own bridge ID, the received switch accepts the other switch as the root
switch. In case the received root bridge ID is higher than its own bridge ID, the received switch ignores the
received BPDU and continue to act as the root switch.
If the priorities of all switches are same, the switch MAC addresses decide the lowest bridge ID and hence
the switch with the lowest MAC address will be elected as the root switch.
6.2 Spanning Tree Support
Supermicro switches support STP, RSTP and MSTP protocols based on standards IEEE 802.1D 2004 and
802.1s.
6.3 Spanning TreeDefaults
Spanning tree global status
Spanning tree port status
Spanning tree compatibility
In MSTP mode, the default
compatibility is MSTP and in RSTP
mode the default compatibility is
Full duplex ports – point to point links
Half duplex ports – shared LAN links