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    spf-options (Protocols OSPF)

    Syntax

    spf-options {delay milliseconds;holddown milliseconds;rapid-runs number;}

    Hierarchy Level

    [edit logical-systems logical-system-name protocols (ospf | ospf3)],[edit logical-systems logical-system-name protocols ospf topology (default | ipv4-multicast | name)],[edit logical-systems logical-system-name protocols ospf3 realm (ipv4-unicast | ipv4-multicast | ipv6-multicast)],[edit logical-systems logical-system-name routing-instances routing-instance-name protocols (ospf | ospf3)],[edit logical-systems logical-system-name routing-instances routing-instance-name protocols ospf topology (default | ipv4-multicast | name)],[edit logical-systems logical-system-name routing-instances routing-instance-name protocols ospf3 realm (ipv4-unicast | ipv4-multicast | ipv6-multicast)],[edit protocols (ospf | ospf3)],[edit protocols ospf topology (default | ipv4-multicast | name)],[edit protocols ospf3 realm (ipv4-unicast | ipv4-multicast | ipv6-multicast)],[edit routing-instances routing-instance-name protocols (ospf | ospf3)],[edit routing-instances routing-instance-name protocols ospf topology (default | ipv4-multicast | name)],[edit routing-instances routing-instance-name protocols ospf3 realm (ipv4-unicast | ipv4-multicast | ipv6-multicast)]

    Release Information

    Statement introduced in Junos OS Release 8.5.

    Statement introduced in Junos OS Release 9.0 for EX Series switches.

    Support for Multitopology Routing introduced in Junos OS Release 9.0.

    Support for Multitopology Routing introduced in Junos OS Release 9.0 for EX Series switches.

    Support for the realm statement introduced in Junos OS Release 9.2.

    Support for the realm statement introduced in Junos OS Release 9.2 for EX Series switches.

    Statement introduced in Junos OS Release 11.3 for the QFX Series.

    Description

    Configure options for running the shortest-path-first (SPF) algorithm. You can configure the following:

    • A delay for when to run the SPF algorithm after a network topology change is detected.
    • The maximum number of times the SPF algorithm can run in succession.
    • A hold-down interval after the SPF algorithm runs the maximum number of times.

    Running the SPF algorithm is usually the beginning of a series of larger system-wide events. For example, the SPF algorithm can lead to interior gateway protocol (IGP) prefix changes, which then lead to BGP nexthop resolution changes. Consider what happens if there are rapid link changes in the network. The local routing device can become overwhelmed. This is why it sometimes makes sense to throttle the scheduling of the SPF algorithm.

    Options

    delay milliseconds—Time interval between the detection of a topology change and when the SPF algorithm runs.

    Range: 50 through 8000 milliseconds

    Default: 200 milliseconds

    holddown milliseconds—Time interval to hold down, or to wait before a subsequent SPF algorithm runs after the SPF algorithm has run the configured maximum number of times in succession.

    Range: 2000 through 20,000 milliseconds

    Default: 5000 milliseconds

    rapid-runs number—Maximum number of times the SPF algorithm can run in succession. After the maximum is reached, the hold down interval begins.

    Range: 1 through 10

    Default: 3

    Required Privilege Level

    routing—To view this statement in the configuration.

    routing-control—To add this statement to the configuration.

     

    Related Documentation

     

    Published: 2014-05-08

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