Configuring Suppression of OSPF Neighbor Relationship Flapping

Procedure

1. Run system-view

   The system view is displayed.

   By default, suppression of OSPF neighbor relationship flapping is enabled globally. To disable this function globally, run the suppress-flapping peer disable command in the OSPF view.

2. Run interface interface-type interface-number

   The interface view is displayed.

   To disable this function on a specified interface, run the ospf suppress-flapping peer disable command in the interface view.

3. On an Ethernet interface, run undo portswitch

   The interface is switched to Layer 3 mode.

   By default, an Ethernet interface works in Layer 2 mode.

   The mode switching function takes effect when the interface only has attribute configurations (for example, shutdown and description configurations). Alternatively, if configuration information supported by both Layer 2 and Layer 3 interfaces exists (for example, mode lacp and lacp system-id configurations), no configuration that is not supported after the working mode of the interface is switched can exist. If unsupported configurations exist on the interface, delete the configurations first and then run the undo portswitch command.

   If many Ethernet interfaces need to be switched to Layer 3 mode, run the undo portswitch batch interface-type { interface-number1 [ to interface-number2 ] } &<1-10> command in the system view to switch these interfaces to Layer 3 mode in batches.

4. Run ospf suppress-flapping peer hold-down interval

   The Hold-down mode is configured, and its duration is set.

   Flapping suppression works in either Hold-down or Hold-max-cost mode.

   • Hold-down mode: In the case of frequent flooding and topology changes during neighbor relationship establishment, interfaces prohibit 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 the maximum value 65535 as the cost of the flapping link during Hold-max-cost suppression, which prevents traffic from passing through the flapping link.

   Flapping suppression can work first in Hold-down mode and then in Hold-max-cost mode after the Hold-down mode exits.

   By default, the Hold-down mode is disabled, and the Hold-max-cost mode is enabled.

   To disable the Hold-max-cost mode, run the ospf suppress-flapping peer hold-max-cost disable command.

5. Run ospf suppress-flapping peer { detecting-interval detecting-interval | threshold threshold | resume-interval resume-interval } ^*

   Detection parameters are configured for suppressing OSPF neighbor relationship flapping.

   • The parameter resume-interval resume-interval specifies the interval for exiting the suppression of OSPF neighbor relationship flapping.

     If the interval between two successive neighbor status changes from Full to ExStart or Down is longer than resume-interval, the flapping_count is reset to 0.

   • If flapping suppression works in Hold-max-cost mode, resume-interval indicates the duration of this mode.

   The value of resume-interval must be greater than that of detecting-interval.

   Flapping suppression detection parameters can be set based on the network requirements on a specified interface. By default, the detection interval of flapping suppression is 60s, the suppression threshold is 10, and the interval for exiting suppression is 120s. Default values are recommended for the detection parameters.

6. Run commit

   The configuration is committed.