Concept Guide

The range is from 4 to 30.
The default is 15 seconds.
2 Change the hello-time parameter.
PROTOCOL MSTP mode
hello-time seconds
NOTE: With large congurations (especially those congurations with more ports) Dell EMC Networking recommends
increasing the hello-time.
The range is from 1 to 10.
The default is 2 seconds.
3 Change the max-age parameter.
PROTOCOL MSTP mode
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.
Example of the forward-delay Parameter
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 inuences 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.
Multiple Spanning Tree Protocol (MSTP)
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