Supermicro SSE-F3548S - 6.10 Port Priority

Supermicro SSE-F3548S/SSE-F3548SR Configuration User’s Guide
169
Step 5
write startup-config
Optional step – saves this spanning tree
configuration to be part of startup
configuration.
The “no spanning-tree priority” command resets the spanning tree switch priority to the
default value (32768). In MST mode, it resets the switch priority for the default MST
instance 0.
The “no spanning-tree mst <instance-id>priority” command resets the spanning tree switch
priority to the default value (32768) for the given MST instance.
The examples below show various ways to configure the spanning tree switch priority.
Configure the spanning tree switch priority as 4096 in RST mode.
SMIS# configure terminal
SMIS(config)# spanning-tree priority 4096
SMIS(config)# end
Configure the spanning tree switch priority as 4096 for the default MST instance 0.
SMIS# configure terminal
SMIS(config)# spanning-tree priority 4096
SMIS(config)# end
Configure the spanning tree switch priority as 4096 for the MST instance 10.
SMIS# configure terminal
SMIS(config)# spanning-tree mst 10 priority 4096
SMIS(config)# end
6.10 Port Priority
When spanning tree detects multiple paths to the root switch in a loop condition, it selects the port with
the lowest path cost as the forwarding port.
In case of multiple ports having the same path cost to the root switch, spanning tree selects the port with
the lowest numeric port priority value as the forwarding port.
When priorities of all the ports are the same, the port with the lowest port identifier gets selected as the
forwarding port.
The port priority used in selection of the root port is the priority of the upstream switch port. Changing
the port priority will affect the root port selection of the downstream switch connected to this port. It will
not affect the root port selection of the switch on which the port priority is changed.