IP Routing: OSPF Configuration Guide, Cisco IOS Release 15M&T
OSPF Retransmissions Limit
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OSPF Retransmissions Limit

OSPF Retransmissions Limit

The OSPF Retransmissions Limit feature adds a limit to the number of retransmissions of database exchange and update packets for both demand and non-demand circuits. The retransmission of these packets stops once this retry limit is reached, thus preventing unnecessary use of the link in continual retransmission of the packets if, for some reason, a neighbor is not responding during adjacency forming. This feature module describes the change in how the Open Shortest Path First (OSPF) protocol handles retransmissions.

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table at the end of this module.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/​go/​cfn. An account on Cisco.com is not required.

Restrictions For OSPF Retransmissions Limit

The limit to the number of retransmissions does not apply for update packets on nonbroadcast multiaccess (NBMA) point-to-multipoint direct circuits. In this situation, the dead timer is used to end communication with non-responding neighbors and thus stop the retransmissions.

Information About OSPF Retransmissions Limit

Overview About OSPF Retransmissions Limit

Cisco IOS Release 12.2(4)T added a limit to the number of retransmissions of database exchange and update packets for both demand and non-demand circuits. The retransmission of these packets stops once this retry limit is reached, thus preventing unnecessary use of the link in continual retransmission of the packets if, for some reason, a neighbor is not responding during adjacency forming.

The limit for both demand circuit and non-demand circuit retransmissions is 24.

The limit-retransmissions command allows you to either remove (disable) the limit or change the maximum number of retransmissions to be a number from 1 to 255.

Benefits

The limit-retransmissions command provides for backward compatibility for previous or other releases of Cisco IOS or other routers that do not have this feature.

How to Configure OSPF Retransmissions Limit

Setting OSPF Retransmission Limits

SUMMARY STEPS

    1.    enable

    2.    configure terminal

    3.    router ospf process-ID

    4.    limit retransmissions{[dc {max-number | disable}] [non-dc {max-number | disable}]}

    5.    end


DETAILED STEPS
     Command or ActionPurpose
    Step 1 enable


    Example:
    Device> enable
     

    Enables privileged EXEC mode.

    • Enter your password if prompted.

     
    Step 2 configure terminal


    Example:
    Device# configure terminal
     

    Enters global configuration mode.

     
    Step 3 router ospf process-ID


    Example:
    Device(config)# router ospf 18
     

    Configures OSPF routing process and enters OSPF router configuration mode.

     
    Step 4limit retransmissions{[dc {max-number | disable}] [non-dc {max-number | disable}]}

    Example:
    Device(config-router)# limit retransmissions dc 5
     

    Sets the limit in the number of retransmissions of database exchange and update packets for both demand and non-demand circuits.

     
    Step 5 end


    Example:
    Device(config-router)# end
     

    Exits address router configuration mode and returns to privileged EXEC mode.

     

    Configuration Examples for OSPF Retransmissions Limit

    Example: Configuring OSPF Retransmissions Limit

    
    router ospf 18
      limit retransmissions dc 5
    
    

    Additional References for OSPF Retransmissions Limit

    Related Documents

    Related Topic

    Document Title

    Cisco IOS commands

    Cisco IOS Master Command List, All Releases

    Configuring OSPF

    IP Routing: OSPF Configuration Guide

    OSPF Commands

    IP Routing: OSPF Command Reference

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    Feature Information for OSPF Retransmissions Limit

    The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.

    Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/​go/​cfn. An account on Cisco.com is not required.

    Table 1 Feature Information for OSPF Retransmissions Limit

    Feature Name

    Releases

    Feature Information

    OSPF Retransmissions Limit

    12.2(11)T

    15.2(1)SY

    The OSPF Retransmissions Limit feature adds a limit to the number of retransmissions of database exchange and update packets for both demand and non-demand circuits. The retransmission of these packets stops once this retry limit is reached, thus preventing unnecessary use of the link in continual retransmission of the packets if, for some reason, a neighbor is not responding during adjacency forming. .

    The following commands were introduced or modified: limit retransmissions .