Concept Guide

• Max-hops — the maximum number of hops a BPDU can travel before a receiving switch discards it.
NOTE: Dell Networking recommends that only experienced network administrators change MSTP parameters. Poorly planned
modication of MSTP parameters can negatively aect network performance.
To change the MSTP parameters, use the following commands on the root bridge.
1 Change the forward-delay parameter.
PROTOCOL MSTP mode
forward-delay seconds
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 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.
Dell(conf-mstp)#forward-delay 16
Dell(conf-mstp)#exit
Dell(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
Dell(conf)#
Multiple Spanning Tree Protocol (MSTP)
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