Contents

• IPv6 NSF and Graceful Restart for MP-BGP IPv6 Address Family
• Finding Feature Information
• Information About IPv6 NSF and Graceful Restart for MP-BGP IPv6 Address Family
• Nonstop Forwarding and Graceful Restart for MP-BGP IPv6 Address Family
• How to Configure IPv6 NSF and Graceful Restart for MP-BGP IPv6 Address Family
• Configuring the IPv6 BGP Graceful Restart Capability
• Configuration Examples for IPv6 NSF and Graceful Restart for MP-BGP IPv6 Address Family
• Example: Configuring the IPv6 BGP Graceful Restart Capability
• Additional References
• Feature Information for IPv6 NSF and Graceful Restart for MP-BGP IPv6 Address Family

IPv6 NSF and Graceful Restart for MP-BGP IPv6 Address Family

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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 IPv6 NSF and Graceful Restart for MP-BGP IPv6 Address Family

Nonstop Forwarding and Graceful Restart for MP-BGP IPv6 Address Family

The graceful restart capability is supported for IPv6 BGP unicast, multicast, and VPNv6 address families, enabling Cisco nonstop forwarding (NSF) functionality for BGP IPv6. The BGP graceful restart capability allows the BGP routing table to be recovered from peers without keeping the TCP state.

NSF continues forwarding packets while routing protocols converge, therefore avoiding a route flap on switchover. Forwarding is maintained by synchronizing the FIB between the active and standby RP. On switchover, forwarding is maintained using the FIB. The RIB is not kept synchronized; therefore, the RIB is empty on switchover. The RIB is repopulated by the routing protocols and subsequently informs FIB about RIB convergence by using the NSF_RIB_CONVERGED registry call. The FIB tables are updated from the RIB, removing any stale entries. The RIB starts a failsafe timer during RP switchover, in case the routing protocols fail to notify the RIB of convergence.

The Cisco BGP address family identifier (AFI) model is designed to be modular and scalable, and to support multiple AFI and subsequent address family identifier (SAFI) configurations.

How to Configure IPv6 NSF and Graceful Restart for MP-BGP IPv6 Address Family

Configuring the IPv6 BGP Graceful Restart Capability

SUMMARY STEPS

1.    enable


2.    configure terminal


3.    router bgp as-number


4.    address-family ipv6 [ vrf vrf-name ] [unicast | multicast | vpnv6]


5.    bgp graceful-restart [restart-time seconds | stalepath-time seconds] [all]

DETAILED STEPS

	Command or Action	Purpose
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 bgp as-number Example: Device(config)# router bgp 65000	Enters router configuration mode for the specified routing process.
Step 4	address-family ipv6 [ vrf vrf-name ] [unicast | multicast | vpnv6] Example: Device(config-router)# address-family ipv6	Specifies the IPv6 address family.
Step 5	bgp graceful-restart [restart-time seconds | stalepath-time seconds] [all] Example: Device(config-router-af)# bgp graceful-restart	Enables the BGP graceful restart capability.

Configuration Examples for IPv6 NSF and Graceful Restart for MP-BGP IPv6 Address Family

Example: Configuring the IPv6 BGP Graceful Restart Capability

In the following example, the BGP graceful restart capability is enabled:

Device# configure terminal
Device(config)# router bgp 65000
Device(config-router)# address-family ipv6
Device(config-router-af)# bgp graceful-restart

In the following example, the restart timer is set to 130 seconds:

Device# configure terminal
Device(config)# router bgp 65000
Device(config-router)# address-family ipv6
Device(config-router-af)# bgp graceful-restart restart-time 130 

In the following example, the stalepath timer is set to 350 seconds:

Device# configure terminal
Device(config)# router bgp 65000
Device(config-router)# address-family ipv6
Device(config-router-af)# bgp graceful-restart stalepath-time 350

Additional References

Related Documents

Related Topic	Document Title
IPv6 addressing and connectivity	IPv6 Configuration Guide
Cisco IOS commands	Cisco IOS Master Command List, All Releases
IPv6 commands	Cisco IOS IPv6 Command Reference
Cisco IOS IPv6 features	Cisco IOS IPv6 Feature Mapping

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 IPv6 NSF and Graceful Restart for MP-BGP IPv6 Address Family

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 IPv6: NSF and Graceful Restart for MP-BGP IPv6 Address Family

Feature Name	Releases	Feature Information
IPv6: NSF and Graceful Restart for MP-BGP IPv6 Address Family	Cisco IOS XE Release 3.1	The graceful restart capability is supported for IPv6 BGP unicast, multicast, and VPNv6 address families, enabling Cisco NSF functionality for BGP IPv6. The BGP graceful restart capability allows the BGP routing table to be recovered from peers without keeping the TCP state.