Dell C1048P Port Extender Networking Configuration Guide for the C9000 Series - Page 711

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 57. Default Values for Port Costs by Interface Port Cost 100-Mb/s Ethernet interfaces 1-Gigabit Ethernet interfaces 10-Gigabit Ethernet interfaces Port Channel with 100 Mb/s Ethernet interfaces Port Channel with 1-Gigabit Ethernet interfaces Port Channel with 10-Gigabit Ethernet interfaces Default Value 200000 20000 2000 180000 18000 1800 To change the port cost or priority of an interface, use the following commands. 1 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.. 2 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. Multiple Spanning Tree Protocol (MSTP) 711