PROTOCOL PVST mode
vlan max-age
The range is from 6 to 40.
The default is 20 seconds.
The values for global PVST+ parameters are given in the output of the show spanning-tree pvst
command.
Modifying Interface PVST+ Parameters
You can adjust two interface parameters (port cost and port priority) to increase or decrease the
probability that a port becomes a forwarding port.
•Port cost — 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 tables lists the default values for port cost by interface.
Table 49. Default Values for Port Cost
Port Cost Default Value
100-Mb/s Ethernet interfaces 200000
1-Gigabit Ethernet interfaces 20000
10-Gigabit Ethernet interfaces 2000
Port Channel with 100 Mb/s Ethernet interfaces 180000
Port Channel with 1-Gigabit Ethernet interfaces 18000
Port Channel with 10-Gigabit Ethernet interfaces 1800
NOTE: The Dell Networking OS implementation of PVST+ uses IEEE 802.1s costs as the default
costs. Other implementations use IEEE 802.1w costs as the default costs. If you are using Dell
Networking systems in a multi-vendor network, verify that the costs are values you intended.
To change the port cost or port priority of an interface, use the following commands.
• Change the port cost of an interface.
INTERFACE mode
spanning-tree pvst vlan cost.
The range is from 0 to 200000.
Refer to the table for the default values.
• Change the port priority of an interface.
INTERFACE mode
spanning-tree pvst vlan priority.
Per-VLAN Spanning Tree Plus (PVST+) 713