Configuring OSPFv3 Neighbor Relationship Flapping Suppression
OSPFv3 neighbor relationship flapping suppression works by delaying OSPFv3 neighbor relationship reestablishment or setting the link cost to the maximum value.
Usage Scenario
If an interface carrying OSPFv3 services alternates between up and down, OSPFv3 neighbor relationship flapping occurs on the interface. During the flapping, OSPFv3 frequently sends Hello packets to reestablish the neighbor relationship, synchronizes LSDBs, and recalculates routes. In this process, a large number of packets are exchanged, adversely affecting neighbor relationship stability, OSPFv3 services, and other OSPFv3-dependent services, such as LDP and BGP. OSPFv3 neighbor relationship flapping suppression can address this problem by delaying OSPFv3 neighbor relationship reestablishment or preventing service traffic from passing through flapping links.
The following steps are optional, and choose them as required.
Pre-configuration Tasks
Before configuring OSPFv3 neighbor relationship flapping suppression, complete the following tasks:
Configure an IP address for each interface to ensure that neighboring devices are reachable at the network layer.
Procedure
- Run system-view
The system view is displayed.
To disable OSPFv3 neighbor relationship flapping suppression globally, run the suppress-flapping peer disable command.
- Run interface interface-type interface-number
The interface view is displayed.
To disable OSPFv3 neighbor relationship flapping suppression from one of the interfaces, run the ospfv3 suppress-flapping peer disable command.
- Run ospfv3 suppress-flapping peer hold-down interval [ instance instance-id ]
The Hold-down mode is configured, and its duration is set.
Flapping suppression works in either of the following modes:
- Hold-down mode: In the case of frequent flooding and topology changes during neighbor relationship establishment, interfaces prevent neighbor relationship reestablishment during Hold-down suppression, which minimizes LSDB synchronization attempts and packet exchanges.
- Hold-max-cost mode: If the traffic forwarding path changes frequently, interfaces use 65535 as the cost of the flapping link during Hold-max-cost suppression, which prevents traffic from passing through the flapping link.
To change the maximum cost of each OSPFv3 link, run the maximum-link-cost cost command.
Flapping suppression can also work first in Hold-down mode and then in Hold-max-cost mode.
To disable the Hold-max-cost mode, run the ospfv3 suppress-flapping peer hold-max-cost disable [ instance instance-id ] command.
- Run ospfv3 suppress-flapping peer { detecting-interval detecting-interval | threshold threshold | resume-interval resume-interval } * [ instance instance-id ]
Detection parameters are configured for OSPFv3 neighbor relationship flapping suppression.
Each OSPFv3 interface on which OSPFv3 neighbor relationship flapping suppression is enabled starts a flapping counter. If the interval between two successive neighbor status changes from Full to a non-Full state is shorter than detecting-interval, a valid flapping_event is recorded, and the flapping_count is incremented by 1.
When the flapping_count reaches or exceeds threshold, flapping suppression takes effect.
If the interval between two successive neighbor status changes from Full to a non-Full state is longer than resume-interval, the flapping_count is reset.
The value of resume-interval must be greater than that of detecting-interval.
Using the default detection parameters is recommended.
- Run quit
Return to the system view.
- Run quit
Return to the user view.
- Run reset ospfv3 process-id suppress-flapping peer [ interface-type interface-number ] [ notify-peer ]
Interfaces are forced to exit from OSPFv3 neighbor relationship flapping suppression.
Interfaces exit from flapping suppression in the following scenarios:- The suppression timer expires.
- The corresponding OSPFv3 process is reset.
- An OSPFv3 neighbor is reset using the reset ospfv3 peer command.
- OSPFv3 neighbor relationship flapping suppression is disabled globally using the suppress-flapping peer disable command in the OSPFv3 view.
- The reset ospfv3 suppress-flapping peer command is run.
- Run commit
The configuration is committed.
Verifying the Configuration
Run the display ospfv3 [ process-id ] interface [ no-peer | area area-id ] [ interface-type interface-number ] command to check the status of OSPFv3 neighbor relationship flapping suppression.