isis timer csnp
Function
The isis timer csnp command configures the interval for sending CSNPs on the broadcast network.
The undo isis timer csnp command restores the default value.
By default, the interval for sending CSNPs on the 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 the broadcast network. | The value is integer ranging from 1 to 65535 seconds. By default, it is 10 seconds. |
| level-1 | Indicates the interval for sending CSNPs in a Level-1 area. | - |
| level-2 | Indicates the interval for sending CSNPs in a Level-2 area. NOTE:
If neither Level-1 nor Level-2 is specified, the interval at which the IS-IS process of the current level sends CSNPs is set by default. |
- |
Views
Ethernet interface view, Ethernet sub-interface view, Eth-Trunk interface view, Eth-Trunk sub-interface view, Tunnel interface view, Loopback interface view, Dialer interface view, VLANIF interface view, Virtual-Template interface view
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 LSP 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.
Configuration Impact
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.