EIGRP IPv6 NSFGR
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EIGRP IPv6 NSF/GRLast Updated: July 26, 2012
The EIGRP IPv6 Nonstop Forwarding (NSF)/Graceful Restart (GR) feature allows an NSF-aware device that is running the Enhanced Interior Gateway Routing Protocol (EIGRP) to forward IPv6 packets while the EIGRP restarts after recovering from a failure. Finding Feature InformationYour 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. Prerequisites for EIGRP IPv6 NSF/GR
Restrictions for EIGRP IPv6 NSF/GR
Information About EIGRP IPv6 NSF/GREIGRP IPv6 NSF/GRThe EIGRP IPv6 NSF/GR feature allows an NSF-aware device that is running EIGRP to forward IPv6 packets along the routes that are known to a device that is performing the switchover operation or if the device is in a failure mode. EIGRP peers retain the adjacency and the route learned from the restarting peer, and the EIGRP peers continue to forward IPv6 packets to the restarting peer. The HA systems retain the forwarding table and continue to forward IPv6 packets until the control plane (EIGRP) has converged on the restarting device. NSF allows forwarding of IPv6 packets while the control plane restarts after recovering from a failure. Graceful Restart (GR) allows topology databases to resynchronize while maintaining neighbor relationships and forwarding paths. EIGRP IPv6 NSF TimersNSF/GR supports three types of timers: the signal timer, the converge timer, and the graceful-restart purge-time timer. The signal timer can be configured to adjust the maximum time of the initial restart period, where the restarting device sends hello packets with the restart (RS) bit set. When the timer expires, if the restarting device has not learned about any neighbor or any NSF-aware neighbor or has not received all the updates from the neighbors, the routing information base (RIB) is notified for convergence. The default value for the signal timer is 20 seconds. The timers nsf signal command is used to configure the signal timer. The converge timer can be configured to adjust the maximum time the restarting device waits for the end-of-table (EOT) indications from all neighbors. The default value for the converge timer is 120 seconds. The timers nsf converge command is used to configure the converge timer. The graceful-restart purge-time timer can be configured to adjust the maximum waiting time to receive the convergent signal from the restarting device. The graceful-restart purge-time timer is used when the NSF-aware peer does not receive the EOT indication from the restarting neighbor. When the graceful-restart purge-time timer expires, the EIGRP peer scans the topology table for the stale routes from the restarting neighbor and changes the stale routes to active, thereby allowing EIGRP peers to find alternate routes instead of waiting during a long switchover operation. The default value for the graceful-restart purge-time timer is 240 seconds. The timers graceful-restart purge-time command is used to configure the graceful-restart purge-time timer. How to Configure EIGRP IPv6 NSF/GR
Enabling EIGRP IPv6 NSF/GRSUMMARY STEPS
DETAILED STEPS Modifying EIGRP IPv6 NSF Timers
SUMMARY STEPS
DETAILED STEPS Verifying the EIGRP IPv6 NSF/GR Configuration
SUMMARY STEPS
DETAILED STEPS Monitoring EIGRP IPv6 NSF/GR EventsPerform this task to monitor EIGRP IPv6 NSF/GR debug events and notifications on an NSF-aware router. DETAILED STEPS Configuration Examples for EIGRP IPv6 NSF/GR
Example: Configuring an EIGRP NSF Converge TimerThe following example shows how to adjust the maximum time the restarting router waits for EOT indications from all neighbors: Device> enable Device# configure terminal Device(config)# router eigrp name Device(config-router)# address-family ipv6 autonomous system 1 Device(config-router-af)# timers nsf converge 60 Device(config-router-af)# end Example: Verifying the Configuration of EIGRP IPv6 NSF/GR on an NSF-Aware DeviceThe following is sample output from the show ipv6 protocols command, which shows that EIGRP NSF is enabled, the graceful-restart purge-time timer is set to 260 seconds, the signal timer is set to 15 seconds, and the converge timer is set to 65 seconds: Device> enable Device# show ipv6 protocols IPv6 Routing Protocol is "connected" IPv6 Routing Protocol is "bgp 1" IGP synchronization is disabled Redistribution: None IPv6 Routing Protocol is "bgp multicast" IPv6 Routing Protocol is "ND" IPv6 Routing Protocol is "eigrp 1" EIGRP-IPv6 VR(name) Address-Family Protocol for AS(1) Metric weight K1=1, K2=0, K3=1, K4=0, K5=0 K6=0 Metric rib-scale 128 Metric version 64bit NSF-aware route hold timer is 260 EIGRP NSF enabled NSF signal timer is 15s NSF converge timer is 65s Router-ID: 10.1.1.1 Topology : 0 (base) Active Timer: 3 min Distance: internal 90 external 170 Maximum path: 16 Maximum hopcount 100 Maximum metric variance 1 Total Prefix Count: 0 Total Redist Count: 0 Interfaces: Redistribution: None Additional ReferencesRelated Documents
Technical Assistance
Feature Information for EIGRP IPv6 NSF/GRThe 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.
Cisco and the Cisco logo are trademarks or registered trademarks of Cisco and/or its affiliates in the U.S. and other countries. To view a list of Cisco trademarks, go to this URL: www.cisco.com/go/trademarks. Third-party trademarks mentioned are the property of their respective owners. The use of the word partner does not imply a partnership relationship between Cisco and any other company. (1110R) Any Internet Protocol (IP) addresses and phone numbers used in this document are not intended to be actual addresses and phone numbers. Any examples, command display output, network topology diagrams, and other figures included in the document are shown for illustrative purposes only. Any use of actual IP addresses or phone numbers in illustrative content is unintentional and coincidental. © 2012 Cisco Systems, Inc. All rights reserved.
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