OSPFv3 Graceful Restart

The graceful restart feature in Open Shortest Path First version 3 (OSPFv3) allows nonstop data forwarding along routes that are already known while the OSPFv3 routing protocol information is being restored.

Information About OSPFv3 Graceful Restart

OSPFv3 Graceful Restart

The graceful restart feature in OSPFv3 allows nonstop data forwarding along routes that are already known while the OSPFv3 routing protocol information is being restored. A device can participate in graceful restart either in restart mode (such as in a graceful-restart-capable device) or in helper mode (such as in a graceful-restart-aware device).

To perform the graceful restart function, a device must be in high availability (HA) stateful switchover (SSO) mode (that is, dual Route Processor (RP)). A device capable of graceful restart will perform the graceful restart function when the following failures occur:

  • A RP failure that results in switchover to standby RP

  • A planned RP switchover to standby RP

The graceful restart feature requires that neighboring devices be graceful-restart aware.

For further information about SSO and nonstop forwarding (NSF), see the Stateful Switchover and Cisco Nonstop Forwarding documents.

How to Enable OSPFv3 Graceful Restart

Enabling OSPFv3 Graceful Restart on a Graceful-Restart-Capable Router

The task can be performed in Cisco IOS XE 3.4S and later releases.

SUMMARY STEPS

  1. enable
  2. configure terminal
  3. router ospfv3 [process-id ]
  4. graceful-restart [restart-interval interval ]

DETAILED STEPS

  Command or Action Purpose

Step 1

enable

Example:


Router> enable

Enables privileged EXEC mode.

  • Enter your password if prompted.

Step 2

configure terminal

Example:


Router# configure terminal

Enters global configuration mode.

Step 3

router ospfv3 [process-id ]

Example:


Router(config)# router ospfv3 1

Enables OSPFv3 router configuration mode for the IPv4 or IPv6 address family.

Step 4

graceful-restart [restart-interval interval ]

Example:


Router(config-rtr)# graceful-restart

Enables the OSPFv3 graceful restart feature on a graceful-restart-capable router.

Enabling OSPFv3 Graceful Restart on a Graceful-Restart-Capable Router

The task can be performed in releases prior to Cisco IOS XE Release 3.4S.

SUMMARY STEPS

  1. enable
  2. configure terminal
  3. ipv6 router ospf process-id
  4. graceful-restart [restart-interval interval ]

DETAILED STEPS

  Command or Action Purpose

Step 1

enable

Example:

Router> enable

Enables privileged EXEC mode.

  • Enter your password if prompted.

Step 2

configure terminal

Example:

Router# configure terminal

Enters global configuration mode.

Step 3

ipv6 router ospf process-id

Example:

Router(config)# ipv6 router ospf 1

Enables OSPFv3 router configuration mode.

Step 4

graceful-restart [restart-interval interval ]

Example:

Router(config-rtr)# graceful-restart

Enables the OSPFv3 graceful restart feature on a graceful-restart-capable router.

Enabling OSPFv3 Graceful Restart on a Graceful-Restart-Aware Router

The task can be performed in Cisco IOS XE Release 3.4S and later releases.

SUMMARY STEPS

  1. enable
  2. configure terminal
  3. router ospfv3 [process-id ]
  4. graceful-restart helper {disable | strict-lsa-checking

DETAILED STEPS

  Command or Action Purpose

Step 1

enable

Example:


Router> enable

Enables privileged EXEC mode.

  • Enter your password if prompted.

Step 2

configure terminal

Example:


Router# configure terminal

Enters global configuration mode.

Step 3

router ospfv3 [process-id ]

Example:


Router(config)# router ospfv3 1

Enables OSPFv3 router configuration mode for the IPv4 or IPv6 address family.

Step 4

graceful-restart helper {disable | strict-lsa-checking

Example:


Router(config-rtr)# graceful-restart helper strict-lsa-checking

Enables the OSPFv3 graceful restart feature on a graceful-restart-aware router.

Example:

What to do next

Enabling OSPFv3 Graceful Restart on a Graceful-Restart-Aware Router

The task can be performed in releases prior to Cisco IOS XE Release 3.4S.

SUMMARY STEPS

  1. enable
  2. configure terminal
  3. ipv6 router ospf process-id
  4. graceful-restart helper {disable | strict-lsa-checking

DETAILED STEPS

  Command or Action Purpose

Step 1

enable

Example:

Router> enable

Enables privileged EXEC mode.

  • Enter your password if prompted.

Step 2

configure terminal

Example:

Router# configure terminal

Enters global configuration mode.

Step 3

ipv6 router ospf process-id

Example:

Router(config)# ipv6 router ospf 1

Enables OSPFv3 router configuration mode.

Step 4

graceful-restart helper {disable | strict-lsa-checking

Example:

Router(config-rtr)# graceful-restart helper strict-lsa-checking

Enables the OSPFv3 graceful restart feature on a graceful-restart-aware router.

Example:
What to do next

Configuration Examples for OSPFv3 Graceful Restart

Example: Enabling OSPFv3 Graceful Restart

Router# show ipv6 ospf graceful-restart
Routing Process "ospf 1"
 Graceful Restart enabled
    restart-interval limit: 120 sec, last restart 00:00:15 ago (took 36 secs)
  Graceful Restart helper support enabled
  Router status : Active
  Router is running in SSO mode
  OSPF restart state : NO_RESTART 
  Router ID 10.1.1.1, checkpoint Router ID 10.0.0.0

The following example shows OSPFv3 information with graceful-restart helper support enabled on a graceful-restart-aware router. 

Router# show ospfv3                 
 Routing Process "ospfv3 1" with ID 10.0.0.1
 Supports IPv6 Address Family
 Event-log enabled, Maximum number of events: 1000, Mode: cyclic
 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
 Number of external LSA 0. Checksum Sum 0x000000
 Number of areas in this router is 0. 0 normal 0 stub 0 nssa
 Graceful restart helper support enabled
 Reference bandwidth unit is 100 mbps
 Relay willingness value is 128
 Pushback timer value is 2000 msecs
 Relay acknowledgement timer value is 1000 msecs
 LSA cache Disabled : current count 0, maximum 1000
 ACK cache Disabled : current count 0, maximum 1000
 Selective Peering is not enabled
 Hello requests and responses will be sent multicast

Additional References

Related Documents

Related Topic

Document Title

IPv6 addressing and connectivity

IPv6 Configuration Guide

Stateful switchover and Cisco nonstop forwarding

High Availability Configuration Guide

Cisco IOS commands

Cisco IOS Master Commands List, All Releases

IPv6 commands

Cisco IOS IPv6 Command Reference

Cisco IOS IPv6 features

Cisco IOS IPv6 Feature Mapping

OSPFv3 Graceful Restart

“OSPF RFC 3623 Graceful Restart Helper Mode” module

OSPFv3 Graceful Restart

“Configuring OSPF ” module

OSPFv3 Graceful Restart

“NSF-OSPF RFC 3623 OSPF Graceful Restart ” module

Standards and RFCs

Standard/RFC

Title

RFCs for IPv6

IPv6 RFCs

MIBs

MIB

MIBs Link

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

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

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 Graceful Restart

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 Graceful Restart

Feature Name

Releases

Feature Information

OSPFv3 Graceful Restart

Cisco IOS XE Release 2.1

The graceful restart feature in OSPFv3 allows nonstop data forwarding along routes that are already known while the OSPFv3 routing protocol information is being restored.

The following commands were introduced or modified: graceful-restart , graceful-restart helper , ipv6 router ospf , router ospfv3 , show ipv6 ospf graceful-restart , show ospfv3 graceful-restart .

Table 2. Feature Information for OSPFv3 Graceful Restart

Feature Name

Releases

Feature Information

OSPFv3 Graceful Restart

Cisco IOS XE Release 17.4

This feature was introduced.