stp timer hello
Function
The stp timer hello command sets the interval of the switching device to send BPDUs, that is, the value of the Hello Time.
The undo stp timer hello command restores the default setting.
By default, the interval of the switch to send BPDUs is 200 centiseconds (2 seconds).
Format
stp [ vlan { vlan-id1 [ to vlan-id2 ] } &<1-10> ] timer hello hello-time
undo stp [ vlan { vlan-id1 [ to vlan-id2 ] } &<1-10> ] timer hello
Parameters
| Parameter | Description | Value |
|---|---|---|
| vlan vlan-id1 [ to vlan-id2 ] | Specifies one or more VLANs in which the Hello timer
value is set.
In the stp timer hello command, you can specify a maximum of 10 VLAN ranges. NOTE:
VLANs can be specified only when VBST is running. |
The value is an integer that ranges from 1 to 4094. |
| hello-time | Specifies the interval of the switch to send BPDUs. |
The value ranges from 100 to 1000, in centiseconds by a step of 100. |
Views
System view or MSTP process view
Usage Guidelines
Usage Scenario
On a network where a spanning tree protocol is enabled, a switching device periodically sends BPDUs to other devices in the same spanning tree at the interval of the Hello Time. Sending BPDUs periodically ensures that the spanning tree is stable. The stp timer hello command can be used to set the BPDU sending interval, that is, the Hello Time.
In a spanning tree, the device closer to the root bridge is the upstream device of another connected device.
Precautions
The value of the Hello Time set on the root bridge is advertised to other devices of the same spanning tree using BPDUs. Then it becomes the value of the Hello Time of all devices in the spanning tree.
2 x (Forward Delay - 1.0 second) ≥ Max Age
Max Age ≥ 2 x (Hello Time + 1.0 second)
Running the stp bridge-diameter command to set the network diameter is recommended. After the stp bridge-diameter command is run, the switching device sets optimum values for the three parameters, Hello Time, Forward Delay, and Max Age.