Configuration Guidelines; Configuration Procedure; Configuring The Timeout Factor - HP 6600 Configuration Manual

calculation process starts. The max age timer is does not take effect on other MSTIs except MSTI 0
(or the CIST).
To prevent network instability, make sure that the timer settings meet the following formulas:
2 × (forward delay – 1 second) ≥ max age
•
Max age ≥ 2 × (hello time + 1 second)
•
HP recommends not manually setting the spanning tree timers. Instead, HP recommends specifying the
network diameter and using the automatically calculated timers based on the network diameter. If the
network diameter uses the default value, the timers also use their default values.
Configure timers on the root bridge only. Timer settings on the root bridge apply to all devices on the
entire switched network.

Configuration 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. HP recommends you to use the default setting.
An appropriate hello time setting enables the device to promptly 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 add the device
burden and waste network resources. HP recommends you to use the default setting.
If the max age timer is too short, the device will frequently launch 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 detect link failures and launch spanning tree calculations promptly, reducing the auto-sensing
capability of the network. HP recommends you to use the default setting.

Configuration procedure

To configure the spanning tree timers:
Step
1. Enter system view.
2. Configure the forward
delay timer.
3. Configure the hello timer.
4. Configure the max age
timer.

Configuring the timeout factor

The timeout factor is a parameter used to calculate the timeout time in the following formula: Timeout time
= timeout factor × 3 × hello time.
Command
system-view
stp timer forward-delay time
stp timer hello time
stp timer max-age time
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Remarks
N/A
Optional.
The default setting is 15 seconds.
Optional.
The default setting is 2 seconds.
Optional.
The default setting is 20 seconds.