The isis timer holding-multiplier command sets the multiplier of the interval for sending Hello packets to change the holdtime of IS-IS neighbor relationship.
The undo isis timer holding-multiplier command restores the default setting.
By default, the multiplier of the interval for sending Hello packets is 3, that is, the neighbor holdtime is three times the interval for sending Hello packets.
isis timer holding-multiplier number [ level-1 | level-2 ]
undo isis timer holding-multiplier [ number ] [ level-1 | level-2 ]
| Parameter | Description | Value |
|---|---|---|
| number | Indicates that the neighbor holdtime is a multiplier of the interval for sending Hello packets. | The value is an integer that ranges from 3 to 1000. The default value is 3. |
| level-1 | Indicates the holdtime of Level-1 neighbors. If the level is not specified, the holdtime is set for both Level-1 and Level-2 neighbors. | - |
| level-2 | Indicates the holdtime of Level-2 neighbors. If the
level is not specified, the holdtime is set for both Level-1 and Level-2
neighbors. NOTE:
Parameters level-1 and level-2 are configured only on a broadcast interface that is enabled with IS-IS. Level-1 and Level-2 Hello packets are sent separately and their intervals must be set respectively. There is only one Hello packet on a point-to-point link. Therefore, level-1 and level-2 parameters are not used. |
- |
Usage Scenario
Devices at both ends of a link establish a neighbor relationship by sending Hello packets to each other. After the neighbor relationship is established, both devices need to send Hello packets at a specified interval to maintain the neighbor relationship. If a device does not receive any Hello packet from its neighbor within a specified period of time, the device considers the neighbor to be Down. The specified time period is known as the neighbor holdtime.
For example, run the isis timer hello command on a local device to set the interval for sending Hello packets to 20s. Then, run the isis timer holding-multiplier 4 command. The holdtime is 80s (four times the interval for sending Hello packets). If the interval for sending Hello packets is changed using the isis timer hello 20 command, the holdtime will be changed accordingly.
Prerequisites
IS-IS has been enabled on the interface using the isis enable command.
Precautions
If the number value is set too large, the local device needs to wait a long time before detecting that the remote device has gone Down. This slows down IS-IS route convergence. If the value of number is set too small, the neighbor relationship will alternate between Up and Down when some Hello packets are lost due to transmission delays and errors on the network. This causes route flapping on the IS-IS network. Therefore, exercise caution when setting the value of number. Set the same interval for sending Hello packets and the same neighbor holdtime for all devices on the IS-IS network is recommended. This is to ensure that all devices detect link failures at the same time and guarantee timely IS-IS route convergence.
If a broadcast interface is emulated as a P2P interface through the isis circuit-type command or then restored to the broadcast interface through the undo isis circuit-type command, the number of Hello packets that IS-IS does not receive from a neighbor before the neighbor is declared Down is restored to the default value.
# Set the number of Level-2 Hello packets that IS-IS does not receive from a neighbor before the neighbor is declared Down to 6 on VLANIF100.
<HUAWEI> system-view [HUAWEI] isis [HUAWEI-isis-1] network-entity 01.0000.0000.0001.00 [HUAWEI-isis-1] quit [HUAWEI] interface vlanif 100 [HUAWEI-Vlanif100] isis enable 1 [HUAWEI-Vlanif100] isis timer holding-multiplier 6 level-2
# Set the number of Level-2 Hello packets that IS-IS does not receive from a neighbor before the neighbor is declared Down to 6 on GE0/0/1.
<HUAWEI> system-view [HUAWEI] isis [HUAWEI-isis-1] network-entity 01.0000.0000.0001.00 [HUAWEI-isis-1] quit [HUAWEI] interface gigabitethernet 0/0/1 [HUAWEI-GigabitEthernet0/0/1] undo portswitch [HUAWEI-GigabitEthernet0/0/1] isis enable 1 [HUAWEI-GigabitEthernet0/0/1] isis timer holding-multiplier 6 level-2