The peer oscillation-dampening command enables BGP to suppress the establishment of a specified peer relationship that flaps continuously.
The peer oscillation-dampening disable command disables BGP from suppressing the establishment of a specified peer relationship that flaps continuously.
The undo peer oscillation-dampening command deletes the configuration of enabling the suppression function for a specified peer.
The undo peer oscillation-dampening disable command deletes the configuration of disabling the suppression function for a specified peer.
By default, BGP suppresses the establishment of a BGP peer relationship that flaps continuously.
Usage Scenario
After a BGP peer relationship is established, the local device learns all routes from the peer and also advertises its local routes to the peer. If the peer relationship is disconnected, the local device deletes all the routes learned from the peer.
Generally, a large number of BGP routes exist, and in this case, a large number of routes change and a large amount of data is processed when the BGP peer relationship is flapping. As a result, a high volume of resources are consumed, causing high CPU usage. To prevent high CPU usage in this case, BGP needs to be enabled to suppress the establishment of the peer relationship if it flaps continuously. Such suppression is implemented for a BGP peer relationship that flaps for more than five times consecutively, and the suppression period increases as the number of flapping times increases. You can run the display bgp peer verbose command to check the remaining time that BGP waits to establish the BGP peer relationship. After the peer relationship stops flapping for a certain period, suppression on the peer relationship establishment is automatically removed. To immediately remove the suppression, you can run the peer oscillation-dampening disable command. Alternatively, you can run a reset command or another command that can cause the peer relationship to be disconnected and re-established.Precautions
If the peer timer connect-retry command is not run, the initial time that BGP waits to establish a peer relationship is 10s. If this command is run, the configured ConnectRetry interval is used as the initial waiting time.
If BGP is enabled to suppress the establishment of a peer relationship that flaps continuously and the initial waiting time is less than 600s, the actual time that BGP waits to establish the peer relationship equals the initial waiting time plus the suppression period. The suppression period increases as the number of flapping times increases until the actual waiting time reaches 600s. If the peer oscillation-dampening [ disable ] command has been run on the local device for a specified peer, the oscillation-dampening set for the peer still takes effect after the peer is added to a peer group regardless of the oscillation-dampening set for this group. If the peer oscillation-dampening [ disable ] command is not run on the local device for a specified peer, the peer uses the oscillation-dampening set for each member in a peer group after the peer is added to the peer group. The group-based oscillation-dampening setting is still effective for the peer after it is removed from the group.