Dell PowerEdge FN I/O Module Configuration Guide 9.10(0.0)

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Modifying the Interface Parameters

You can adjust two interface parameters to increase or decrease the probability that a port becomes a forwarding port.

Port cost is a value that is based on the interface type. The greater the port cost, the less likely the port is selected to be a forwarding port.
Port priority influences the likelihood that a port is selected to be a forwarding port in case that several ports have the same port cost.

The following lists the default values for port cost by interface.

Table 1. Default Values for Port Costs by Interface
Port Cost	Default Value
1000-Mb/s Ethernet interfaces	20000
40-Gigabit Ethernet interfaces	1400
10-Gigabit Ethernet interfaces	2000
Port Channel with one 10–Gigabit Ethernet interface	2000
Port Channel with one 40-Gigabit Ethernet interface	1400
Port Channel with two 10-Gigabit Ethernet interfaces	1800
Port Channel with two 40-Gigabit Ethernet interfaces	600

To change the port cost or priority of an interface, use the following commands.

Change the port cost of an interface. INTERFACE mode spanning-tree msti number cost cost The range is from 0 to 200000. For the default, refer to the default values shown in the table.
Change the port priority of an interface. INTERFACE mode spanning-tree msti number priority priority The range is from 0 to 240, in increments of 16. The default is 128.

To view the current values for these interface parameters, use the show config command from INTERFACE mode.