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Junos CLI Reference
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show policy damping

date_range 19-Nov-23

Syntax

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show policy damping 
<logical-system (all | logical-system-name)>

Syntax (EX Series Switch and QFX Series)

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show policy damping 

Description

Display information about BGP route flap damping parameters.

Options

none

Display information about BGP route flap damping parameters.

logical-system (all | logical-system-name)

(Optional) Perform this operation on all logical systems or on a particular logical system.

Additional Information

In the output from this command, figure-of-merit values correlate with the probability of future instability of a routing device. Routes with higher figure-of-merit values are suppressed for longer periods of time. The figure-of-merit value decays exponentially over time. A figure-of-merit value of zero is assigned to each new route. The value is increased each time the route is withdrawn or readvertised, or when one of its path attributes changes.

Required Privilege Level

view

Output Fields

Table 1 describes the output fields for the show policy damping command. Output fields are listed in the approximate order in which they appear.

Table 1: show policy damping Output Fields

Field Name

Field Description

Halflife

Decay half-life, in minutes. The value represents the period during which the accumulated figure-of-merit value is reduced by half if the route remains stable. If a route has flapped, but then becomes stable, the figure-of-merit value for the route decays exponentially. For example, for a route with a figure-of-merit value of 1500, if no incidents occur, its figure-of-merit value is reduced to 750 after 15 minutes and to 375 after another 15 minutes.

Reuse merit

Figure-of-merit value below which a suppressed route can be used again. A suppressed route becomes reusable when its figure-of-merit value decays to a value below a reuse threshold, and the route once again is considered usable and can be installed in the forwarding table and exported from the routing table.

Suppress/cutoff merit

Figure-of-merit value above which a route is suppressed for use or inclusion in advertisements. When a route's figure-of-merit value reaches a particular level, called the cutoff or suppression threshold, the route is suppressed. When a route is suppressed, the routing table no longer installs the route into the forwarding table and no longer exports this route to any of the routing protocols.

Maximum suppress time

Maximum hold-down time, in minutes. The value represents the maximum time that a route can be suppressed no matter how unstable it has been before this period of stability.

Computed values

  • Merit ceiling—Maximum merit that a flapping route can collect.

  • Maximum decay—Maximum decay half-life, in minutes.

Sample Output

show policy damping

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user@host> show policy damping 
Default damping information:
  Halflife: 15 minutes
  Reuse merit: 750 Suppress/cutoff merit: 3000
  Maximum suppress time: 60 minutes
  Computed values:
    Merit ceiling: 12110
    Maximum decay: 6193
Damping information for "standard-damping":
  Halflife: 10 minutes
  Reuse merit: 4000 Suppress/cutoff merit: 8000
  Maximum suppress time: 30 minutes
  Computed values:
    Merit ceiling: 32120
    Maximum decay: 12453

Release Information

Command introduced before Junos OS Release 7.4.

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