Supermicro SSE-F3548S/SSE-F3548SR Configuration User’s Guide
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The “no spanning-tree port-priority” command resets the spanning tree port priority to the
default value (128). In MST mode, it resets the port priority for the default MST instance 0.
The “no spanning-tree mst <instance-id>port-priority” command resets the spanning tree
port priority to the default value (128) for the given MST instance.
The examples below show various ways to configure the spanning tree port priority.
Configure the spanning tree port priority as 208 in RST mode on ports fx 0/1 and fx 0/2.
SMIS# configure terminal
SMIS(config)# interface range cx 0/1-2
SMIS(config-if)# spanning-tree port-priority 208
SMIS(config-if)# end
Configure the spanning tree port priority as 112 for the default MST instance 0 on port fx 0/1
SMIS# configure terminal
SMIS(config)# interface fx 0/1
SMIS(config-if)# spanning-tree port-priority 112
SMIS(config-if)# end
Configure the spanning tree port priority as 64 for the MST instance 10 on port cx 0/1
SMIS# configure terminal
SMIS(config)# interface cx 0/1
SMIS(config-if)# spanning-tree mst 10 port-priority 64
SMIS(config-if)# end
6.11
Path Cost
When spanning tree detects multiple paths to root switches in a loop condition, it selects the port with
lowest path cost as the forwarding port. If multiple ports have the same path cost to the root switch,
spanning tree selects the port with lowest numeric port priority value as the forwarding port.
The default path cost for the ports are calculated based on the port speed. The table below shows the
default path costs for different speeds.
Port Speed
Default Path Cost
10 Mbps
2000000
100 Mbps
200000
1 Gbps
20000
10 Gbps
2000
