Administrator Guide

max-age seconds
The range is from 6 to 40.
The default is 20 seconds.
4. Change the max-hops parameter.
PROTOCOL MSTP mode
max-hops number
The range is from 1 to 40.
The default is 20.
To view the current values for MSTP parameters, use the show running-config spanning-tree mstp command from
EXEC privilege mode.
DellEMC(conf-mstp)#forward-delay 16
DellEMC(conf-mstp)#exit
DellEMC(conf)#do show running-config spanning-tree mstp
!
protocol spanning-tree mstp
no disable
name my-mstp-region
MSTI 1 VLAN 100
MSTI 2 VLAN 200-300
forward-delay 16
MSTI 2 bridge-priority 4096
DellEMC(conf)#
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 63. Default Values for Port Costs by Interface
Port Cost Default Value
100-Mb/s Ethernet interfaces 200000
1-Gigabit Ethernet interfaces 20000
10-Gigabit Ethernet interfaces 2000
25-Gigabit Ethernet interfaces 800
40-Gigabit Ethernet interfaces 500
50-Gigabit Ethernet interfaces 400
100-Gigabit Ethernet interfaces 200
Port Channel with 100 Mb/s Ethernet interfaces 100000
Port Channel with 1-Gigabit Ethernet interfaces 10000
Port Channel with 10-Gigabit Ethernet interfaces 1000
Port Channel with 25-Gigabit Ethernet interfaces 400
Port Channel with 50-Gigabit Ethernet interfaces 200
Port Channel with 100-Gigabit Ethernet interfaces 100
To change the port cost or priority of an interface, use the following commands.
566
Multiple Spanning Tree Protocol (MSTP)