IP Routing: OSPF Configuration Guide, Cisco IOS XE Release 3S
OSPFv3 NSR
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OSPFv3 NSR

OSPFv3 NSR

The OSPFv3 NSR feature allows a router with redundant Route Processors (RPs) to maintain its Open Shortest Path First (OSPF) state and adjacencies across planned and unplanned RP switchovers. It does this by checkpointing state information from OSPFv3 on the active RP to the standby RP. Later, following a switchover to the standby RP, OSPFv3 can use this checkpointed information to continue operation without interruption.

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.

Information About OSPFv3 NSR

OSPFv3 NSR Functionality

Although OSPFv3 NSR serves a similar function to the OSPFv3 graceful restart feature, it works differently. With graceful restart, OSPFv3 on the newly active standby RP initially has no state information, so it uses extensions to the OSPFv3 protocol to recover its state from neighboring OSPFv3 devices. For this to work, the neighbors must support the graceful restart protocol extensions and be able to act as helpers to the restarting device. They must also continue forwarding data traffic to the restarting device while this recovery is taking place.

With NSR, by contrast, the device performing the switchover preserves its state internally, and in most cases the neighbors are unaware that anything has happened. Because no assistance is needed from neighboring devices, NSR can be used in situations where graceful restart cannot; for example, graceful restart is unreliable in networks where not all the neighbors implement the graceful restart protocol extensions or where the network topology changes during the recovery.


Note


When NSR is enabled, the responsiveness and scalability of OSPF is degraded. The performance degradation happens because OSPF uses cpu and memory to checkpoint data to the standby Route Processor (RP).


How to Configure OSPFv3 NSR

Configuring OSPFv3 NSR

Perform this task to configure OSPFv3 NSR.


Note


Devices that do not support NSR will not accept the nsr (OSPFv3) command.


SUMMARY STEPS

    1.    enable

    2.    configure terminal

    3.    router ospfv3 process-id

    4.    nsr

    5.    end

    6.    show ospfv3 [process-id] [address-family] nsr


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 ospfv3 process-id


    Example:
    Device(config)# router ospfv3 109
     

    Places the device in router configuration mode and configures an OSPFv3 routing process.

     
    Step 4 nsr


    Example:
    Device(config-router)# nsr
     

    Configures NSR.

     
    Step 5 end


    Example:
    Device(config-router)# end
     

    Exits router configuration mode and returns to privileged EXEC mode.

     
    Step 6 show ospfv3 [process-id] [address-family] nsr


    Example:
    Device# show ospfv3 109 nsr
     

    Displays OSPFv3 NSR status information.

     

    Configuring OSPFv3 NSR for an Address Family

    In address family configuration mode you can configure NSR for a particular address family. Perform this task to enable OSPFv3 NSR for an address family.


    Note


    Devices that do not support NSR will not accept the nsr (OSPFv3) command.


    SUMMARY STEPS

      1.    router ospfv3 process-id

      2.    address-family {ipv4 | ipv6} unicast [vrf vrf-name]

      3.    nsr [disable]


    DETAILED STEPS
       Command or ActionPurpose
      Step 1 router ospfv3 process-id


      Example:
      Device(config)# router ospfv3 109
       

      Places the device in router configuration mode and configures an OSPFv3 routing process.

       
      Step 2 address-family {ipv4 | ipv6} unicast [vrf vrf-name]


      Example:
      Device(config-router)# address-family ipv4 unicast
       

      Enters IPv4 or IPv6 address family configuration mode for OSPFv3 router configuration mode.

       
      Step 3 nsr [disable]


      Example:
      Device(config-router-af)# nsr 
       

      Enables NSR for the address family that is configured.

       

      Disabling OSPFv3 NSR for an Address Family

      In address family configuration mode the optional disable keyword is available for the nsr command. Perform this task to disable OSPFv3 NSR for an address family.

      SUMMARY STEPS

        1.    router ospfv3 process-id

        2.    address-family {ipv4 | ipv6} unicast [vrf vrf-name]

        3.    nsr [disable]


      DETAILED STEPS
         Command or ActionPurpose
        Step 1 router ospfv3 process-id


        Example:
        Device(config)# router ospfv3 109
         

        Places the device in router configuration mode and configures an OSPFv3 routing process.

         
        Step 2 address-family {ipv4 | ipv6} unicast [vrf vrf-name]


        Example:
        Device(config-router)# address-family ipv6 unicast
         

        Enters IPv4 or IPv6 address family configuration mode for OSPFv3 router configuration mode.

         
        Step 3 nsr [disable]


        Example:
        Device(config-router-af)# nsr disable
         

        Disables NSR for the address family that is configured.

         

        Troubleshooting Tips

        OSPFv3 NSR can increase the amount of memory used by the OSPFv3 device process. To determine how much memory OSPFv3 is currently using without NSR, you can use the show processes and show processes memory commands:

        Device# show processes
         | include OSPFv3
         276 Mwe  133BE14         1900       1792    1060 8904/12000  0 OSPFv3-1 Router
         296 Mwe  133A824           10        971      10 8640/12000  0 OSPFv3-1 Hello
        

        Process 276 is the OSPFv3 device process that is to be checked. The show processes memory command is used to display its current memory use:

        Device# show processes memory 276
        Process ID: 276
        Process Name: OSPFv3-1 Router
        Total Memory Held: 4454800 bytes 

        In this case OSPFv3 is using 4,454,800 bytes or approximately 4.5 megabytes (MB). OSPFv3 NSR could double this for brief periods, so you should make sure the device has at least 5 MB of free memory before enabling OSPFv3 NSR.

        Configuration Examples for OSPFv3 NSR

        Example Configuring OSPFv3 NSR

        The following example shows how to configure OSPFv3 NSR and verify that it is enabled:

        Device(config)# router ospfv3 1
        Device(config-router)# nsr
        Device(config-router)# end
        Device# show ospfv3 1
          OSPFv3 1 address-family ipv4
          Router ID 10.0.0.1
          Supports NSSA (compatible with RFC 3101)
          Event-log enabled, Maximum number of events: 1000, Mode: cyclic
          It is an area border and autonomous system boundary router
          Redistributing External Routes from,
          Router is not originating router-LSAs with maximum metric
          Initial SPF schedule delay 5000 msecs
          Minimum hold time between two consecutive SPFs 10000 msecs
          Maximum wait time between two consecutive SPFs 10000 msecs
          Minimum LSA interval 5 secs
          Minimum LSA arrival 1000 msecs
          LSA group pacing timer 240 secs
          Interface flood pacing timer 33 msecs
          Retransmission pacing timer 66 msecs
          Retransmission limit dc 24 non-dc 24
          Number of external LSA 0. Checksum Sum 0x000000
          Number of areas in this router is 3. 2 normal 0 stub 1 nssa
          Non-Stop Routing enabled
          Graceful restart helper support enabled
          Reference bandwidth unit is 100 mbps
          RFC1583 compatibility enabled
             Area BACKBONE(0) (Inactive)
                 Number of interfaces in this area is 1
                 SPF algorithm executed 3 times
                 Number of LSA 6. Checksum Sum 0x03C938
                 Number of DCbitless LSA 0
                 Number of indication LSA 0
                 Number of DoNotAge LSA 0
                 Flood list length 0
             Area 1
                 Number of interfaces in this area is 3
                 SPF algorithm executed 3 times
                 Number of LSA 6. Checksum Sum 0x024041
                 Number of DCbitless LSA 0
                 Number of indication LSA 0
                 Number of DoNotAge LSA 0
                 Flood list length 0
             Area 3
                 Number of interfaces in this area is 1
                 It is a NSSA area
                 Perform type-7/type-5 LSA translation
                 SPF algorithm executed 4 times
                 Number of LSA 5. Checksum Sum 0x024910
                 Number of DCbitless LSA 0
                 Number of indication LSA 0
                 Number of DoNotAge LSA 0
                 Flood list length 0
        
          OSPFv3 1 address-family ipv6
          Router ID 10.0.0.1
          Supports NSSA (compatible with RFC 3101)
          Event-log enabled, Maximum number of events: 1000, Mode: cyclic
          It is an area border and autonomous system boundary router
          Redistributing External Routes from,
             ospf 2
          Router is not originating router-LSAs with maximum metric
          Initial SPF schedule delay 5000 msecs
          Minimum hold time between two consecutive SPFs 10000 msecs
          Maximum wait time between two consecutive SPFs 10000 msecs
          Minimum LSA interval 5 secs
          Minimum LSA arrival 1000 msecs
          LSA group pacing timer 240 secs
          Interface flood pacing timer 33 msecs
          Retransmission pacing timer 66 msecs
          Retransmission limit dc 24 non-dc 24
          Number of external LSA 0. Checksum Sum 0x000000
          Number of areas in this router is 3. 2 normal 0 stub 1 nssa
          Non-Stop Routing enabled
          Graceful restart helper support enabled
          Reference bandwidth unit is 100 mbps
          RFC1583 compatibility enabled
             Area BACKBONE(0) (Inactive)
                 Number of interfaces in this area is 2
                 SPF algorithm executed 2 times
                 Number of LSA 6. Checksum Sum 0x02BAB7
                 Number of DCbitless LSA 0
                 Number of indication LSA 0
                 Number of DoNotAge LSA 0
                 Flood list length 0
             Area 1
                 Number of interfaces in this area is 4
                 SPF algorithm executed 2 times
                 Number of LSA 7. Checksum Sum 0x04FF3A
                 Number of DCbitless LSA 0
                 Number of indication LSA 0
                 Number of DoNotAge LSA 0
                 Flood list length 0
             Area 3
                 Number of interfaces in this area is 1
                 It is a NSSA area
                 Perform type-7/type-5 LSA translation
                 SPF algorithm executed 3 times
                 Number of LSA 5. Checksum Sum 0x011014
                 Number of DCbitless LSA 0
                 Number of indication LSA 0
                 Number of DoNotAge LSA 0
                 Flood list length 0
        

        The output shows that OSPFv3 NSR is configured.

        Example Verifying OSPFv3 NSR

        The following example shows how to verify OSPFv3 NSR status:

        Device# show ospfv3 1 nsr
          Active RP
          Operating in duplex mode
          Redundancy state: ACTIVE
          Peer redundancy state: STANDBY HOT
          Checkpoint peer ready
          Checkpoint messages enabled
          ISSU negotiation complete
          ISSU versions compatible
        
        
                   OSPFv3 1 address-family ipv4 (router-id 10.0.0.1)
          NSR configured
          Checkpoint message sequence number: 29
          Standby synchronization state: synchronized
          Bulk sync operations:  1
          Next sync check time:  12:00:14.956 PDT Wed Jun 6 2012
          LSA Count: 17, Checksum Sum 0x00085289
        
        
                   OSPFv3 1 address-family ipv6 (router-id 10.0.0.1)
          NSR configured
          Checkpoint message sequence number: 32
          Standby synchronization state: synchronized
          Bulk sync operations:  1
          Next sync check time:  12:00:48.537 PDT Wed Jun 6 2012
          LSA Count: 18, Checksum Sum 0x0008CA05
        

        The output shows that OSPFv3 NSR is configured and that OSPFv3 on the standby RP is fully synchronized and ready to continue operation if the active RP fails or if a manual switchover is performed.

        Additional References

        Related Documents

        Related Topic

        Document Title

        Cisco IOS commands

        Cisco IOS Master Commands List, All Releases

        OSPF commands

        Cisco IOS IP Routing: OSPF Command Reference

        OSPFv3 Address Families

        OSPFv3 Address Families module

        Standards

        Standards

        Title

        No new or modified standards are supported by this feature, and support for existing standards has not been modified by this feature.

        MIBs

        MIBs

        MIBs Link

        No new or modified MIBs are supported by this feature, and support for existing MIBs has not been modified by this feature.

        To locate and download MIBs for selected platforms, Cisco software releases, and feature sets, use Cisco MIB Locator found at the following URL:

        http:/​/​www.cisco.com/​go/​mibs

        RFCs

        RFCs

        Title

        RFC 5187.

        OSPFv3 Graceful Restart

        Technical Assistance

        Description

        Link

        The Cisco Support and Documentation website provides online resources to download documentation, software, and tools. Use these resources to install and configure the software and to troubleshoot and resolve technical issues with Cisco products and technologies. Access to most tools on the Cisco Support and Documentation website requires a Cisco.com user ID and password.

        http:/​/​www.cisco.com/​cisco/​web/​support/​index.html

        Feature Information for OSPFv3 NSR

        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 OSPFv3 NSR

        Feature Name

        Releases

        Feature Information

        OSPFv3 NSR

        15.1(2)SY

        15.2(4)S

        The OSPFv3 NSR feature allows a router with redundant RPs to maintain its OSPFv3 state and adjacencies across planned and unplanned RP switchovers.

        The following commands were introduced or modified: clear ospfv3 nsr, nsr (OSPFv3), show ospfv3 nsr.