Reference Guide

Multiple Spanning Tree Protocol (MSTP) | 613
Figure 32-6. Viewing the MSTP Region Name and Revision
Modifying Global Parameters
The root bridge sets the values for forward-delay, hello-time, max-age, and max-hops and overwrites the
values set on other MSTP bridges.
• Forward-delay is the amount of time an interface waits in the Listening State and the Learning State
before it transitions to the Forwarding State.
• Hello-time is the time interval in which the bridge sends MSTP Bridge Protocol Data Units (BPDUs).
• Max-age is the length of time the bridge maintains configuration information before it refreshes that
information by recomputing the MST topology.
• Max-hops is the maximum number of hops a BPDU can travel before a receiving switch discards it.
To change MSTP parameters, use the following commands on the root bridge:
View the current values for MSTP parameters using the
show running-config spanning-tree mstp command
from EXEC privilege mode.
Note: Dell Networking recommends that only experienced network administrators change MSTP
parameters. Poorly planned modification of MSTP parameters can negatively impact network performance.
Task Command Syntax Command Mode
Change the forward-delay parameter.
• Range: 4 to 30
• Default: 15 seconds
forward-delay seconds PROTOCOL MSTP
Change the hello-time parameter.
Note: With large configurations (especially those with more
ports) Dell Networking recommends that you increase the
hello-time.
Range: 1 to 10
Default: 2 seconds
hello-time seconds PROTOCOL MSTP
Change the max-age parameter.
Range: 6 to 40
Default: 20 seconds
max-age seconds PROTOCOL MSTP
Change the max-hops parameter.
Range: 1 to 40
Default: 20
max-hops number PROTOCOL MSTP
Dell(conf-mstp)#name my-mstp-region
Dell(conf-mstp)#exit
Dell(conf)#do show spanning-tree mst config
MST region name: my-mstp-region
Revision: 0
MSTI VID
1 100
2 200-300