3Com MSR 50 manual Stp timer hello, Syntax stp timer hello centi-seconds Undo stp timer hello, 625

625

forwarding state, and must wait a certain period of time before it transitions from one state to another to keep synchronized with the remote device during state transition. The forward delay timer set on the root bridge determines the time interval of state transition.

If the current device is the root bridge, the state transition interval of the device depends on the set forward delay value; for a secondary root bridge, its state transition interval is determined by the forward delay timer set on the root bridge.

The setting of the hello time, forward delay and max age timers must meet the following formulae.

■2 ⋅ (forward delay - 1 second) ƒ max age

■Max age ƒ 2 ⋅ (hello Time + 1 second)

MSTP can work effectively on the entire network only when the above-mentioned conditions are met; otherwise, network instability will frequently occur. We recommend that you specify the network diameter of the switched network in the stp bridge-diameterbridge-numbercommand and let MSTP automatically calculate an optimal setting of these three timers.

Related commands: stp timer hello, stp timer max-age, and stp bridge-diameter.

Examples # Set the forward delay timer of the device to 2,000 centiseconds.

<Sysname> system-view

[Sysname] stp timer forward-delay 2000

stp timer hello

Syntax stp timer hello centi-seconds

undo stp timer hello

View System view

Parameters centi-seconds: Hello time, in the range 100 to 1,000 (in centiseconds). This argument must be a multiple of 100.

Description Use the stp timer hello command to set the hello time of the device.

Use the undo stp timer hello command to restore the hello time of the device to the default setting.

By default, the hello time is set to 200 centiseconds.

Hello time is the time interval at which MSTP-compliant devices send configuration BPDUs to maintain spanning tree stability. If a device fails to receive configuration BPDUs within the set period of time, a new spanning tree computing process will be triggered due to timeout. The root bridge sends configuration BPDUs at the