Configuration Procedure; Configuring The Timeout Factor - HP 6125XLG Configuration Manual

network convergence might take a long time. HP recommends that you use the automatically
calculated value.
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 mistakes packet
loss for a link failure and triggers a new spanning tree calculation process. If the hello time is too
short, the device frequently sends the same configuration BPDUs, which waste device and network
resources. HP recommends that you use the automatically calculated value.
If the max age timer is too short, the device frequently begins spanning tree calculations and might
•
mistake network congestion as a link failure. If the max age timer is too long, the device might fail
to promptly detect link failures and quickly launch spanning tree calculations, reducing the
auto-sensing capability of the network. HP recommends that you use the automatically calculated
value.

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 decide the timeout period, in the following formula: Timeout
period = timeout factor × 3 × hello time.
In a stable network, each non-root-bridge device forwards configuration BPDUs to the downstream
devices at the hello time interval to detect link failures. If a device does not receive a BPDU from the
upstream device within nine times the hello time, it assumes that the upstream device has failed. Then, it
starts a new spanning tree calculation process.
An upstream device might be too busy to forward configuration BPDUs in time, for example, many Layer
2 interfaces are configured on the upstream device. As a result, the downstream device fails to receive a
BPDU within the timeout period and then starts an undesired spanning tree calculation. The calculation
might fail, and it also wastes network resources. To prevent undesired spanning tree calculation and save
network resources on a stable network, you can set the timeout factor to 5, 6, or 7.
Command
system-view
•
In STP/RSTP/MSTP mode:
stp timer forward-delay time
•
In PVST mode:
stp vlan vlan-id-list timer
forward-delay time
•
In STP/RSTP/MSTP mode:
stp timer hello time
•
In PVST mode:
stp vlan vlan-id-list timer hello time
•
In STP/RSTP/MSTP mode:
stp timer max-age time
•
In PVST mode:
stp vlan vlan-id-list timer max-age
time
97
Remarks
N/A
The default setting is 15 seconds.
The default setting is 2 seconds.
The default setting is 20 seconds.