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calculate the timers based on the network diameter. If the network diameter uses the default value,
the timers also use their default values.
Configure the timers on the root bridge only, and the timer settings on the root bridge apply to all
devices on the entire switched network.
Configuration restrictions and guidelines
•
The length of the forward delay timer is related to the network diameter of the switched network.
The larger the network diameter is, the longer the forward delay time should be. If the forward
delay timer is too short, temporary redundant paths might occur. If the forward delay timer is too
long, network convergence might take a long time. Hewlett Packard Enterprise recommends
you to use the default setting.
•
An appropriate hello time setting enables the device to quickly detect link failures on the
network without using excessive network resources. If the hello time is too long, the device will
mistake packet loss as a link failure and trigger a new spanning tree calculation process. If the
hello time is too short, the device will frequently send the same configuration BPDUs, which
adds the device burden and wastes network resources. Hewlett Packard Enterprise
recommends you to use the default setting.
•
If the max age timer is too short, the device will frequently begin spanning tree calculation and
might mistake network congestion as a link failure. If the max age timer is too long, the device
might fail to quickly detect link failures and begin spanning tree calculations, reducing the
auto-sensing capability of the network. Hewlett Packard Enterprise recommends you to use the
default setting.
Configuration procedure
To configure the spanning tree timers:
Step Command
Remarks
1.
Enter system view.
system-view
N/A
2.
Configure the forward
delay timer.
•
In STP/RSTP/MSTP mode:
stp timer forward-delay time
•
In PVST mode:
stp vlan
vlan-list
timer
forward-delay time
Optional.
Use one of the commands.
The default setting is 15
seconds.
3.
Configure the hello
timer.
•
In STP/RSTP/MSTP mode:
stp timer hello time
•
In PVST mode:
stp vlan
vlan-list
timer hello time
Optional.
Use one of the commands.
The default setting is 2
seconds.
4.
Configure the max age
timer.
•
In STP/RSTP/MSTP mode:
stp
timer max-age time
•
In PVST mode:
stp
vlan
vlan-list
timer max-age time
Optional.
Use one of the commands.
The default setting is 20
seconds.
Configuring the timeout factor
The timeout factor is a parameter used to decide the timeout time, in the following formula: Timeout
time = timeout factor × 3 × hello time.