• Change the hello-time parameter.
PROTOCOL PVST mode
vlan hello-time
NOTE: With large configurations (especially those configurations with more ports), Dell
Networking recommends increasing the hello-time.
The range is from 1 to 10.
The default is 2 seconds.
• Change the max-age parameter.
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 47. Default Values for Port Cost
Port Cost Default Value
1000-Mb/s Ethernet interfaces 20000
10-Gigabit Ethernet interfaces 2000
40-Gigabit Ethernet interfaces 1400
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
712
Per-VLAN Spanning Tree Plus (PVST+)
