isis timer csnp
Function
The isis timer csnp command sets the interval for sending CSNPs on a broadcast network.
The undo isis timer csnp command restores the default setting.
By default, the interval for sending CSNPs on a broadcast network is 10 seconds.
Format
isis timer csnp csnp-interval [ level-1 | level-2 ]
undo isis timer csnp [ csnp-interval ] [ level-1 | level-2 ]
Parameters
| Parameter | Description | Value |
|---|---|---|
| csnp-interval | Specifies the interval for sending CSNPs on a broadcast network. | The value is an integer that ranges from 1 to 65535, in seconds. The default value is 10 seconds. |
| level-1 | Indicates the interval for sending Level-1 CSNPs. If no level is specified, the interval for the IS-IS process of the current level to send CSNP packets is set by default. | - |
| level-2 | Indicates the interval for sending Level-2 CSNPs. If no level is specified, the interval for the IS-IS process of the current level to send CSNP packets is set by default. | - |
Usage Guidelines
Usage Scenario
In a broadcast network, a DIS sends CSNPs periodically to enable all devices to synchronize LSDBs with one another. If a device finds that the local LSDB does not have a specific LSP or an existing LSPs is not the latest one after the device has received a CSNP, the device will send a PSNP to request the corresponding LSP. Only a DIS sends CSNPs periodically. Therefore, the isis timer csnp command will take effect only on a broadcast interface of the DIS. This command can be used to set an interval for sending CSNPs in an area at a specified level. A router may be elected as a DIS in both Level-1 and Level-2 areas. Therefore, you can set different intervals at which the DIS sends CSNPs in Level-1 and Level-2 areas.
Precautions
The IS-IS route convergence speed depends on the LSDB synchronization speed. Therefore, reducing the interval for sending CSNPs can speed up LSDB synchronization and IS-IS route convergence. If the interval is set too small, however, the DIS will send CSNPs frequently. This causes high CPU, memory, and network bandwidth usage and affects services.
If the isis circuit-type command is run to emulate the interface as a P2P interface, the isis timer csnp command becomes invalid on the interface; after the undo isis circuit-type command is run to restore the broadcast interface, the interval for sending CSNPs is restored to the default setting.
Example
# Set the interval for sending Level-2 CSNPs to 15 seconds 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 csnp 15 level-2
# Set the interval for sending Level-2 CSNPs to 15 seconds 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 csnp 15 level-2