Configuring ND

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1 Overview

This document provides an overview of the Neighbor Discovery (ND) protocol as supported on the SmartEdge® router and describes the tasks used to configure, monitor, and administer the ND protocol. This document also provides ND protocol configuration examples.

The SmartEdge router uses the Neighbor Discovery (ND) protocol for IPv6 to determine the link-layer addresses for neighbors known to reside on attached links and to quickly purge cached values that become invalid.

The IPv6 ND protocol for the SmartEdge router corresponds to a combination of the IPv4 Address Resolution Protocol (ARP) and Internet Control Message Protocol (ICMP) Router Discovery Protocol (IRDP). The ND protocol is described in RFC 2461, Neighbor Discovery for IP Version 6 (IPv6).

The ND protocol provides many improvements over the IPv4 set of protocols, some of which are included here:

2 Configuration and Operations Tasks

To configure an ND router, perform the tasks described in Table 1; enter all commands in ND router configuration mode, unless otherwise noted.

*Table 1 Configure an ND Router*
Step	Task	Root Command	Notes
1.	Create or select the context for the ND router.	context	Enter this command in global configuration mode.
2.	Create the interface for the ND router.	interface	Enter this command in context configuration mode.
3.	Specify an IPv6 IP address for the interface.	ipv6 address	Enter this command in interface configuration mode.
4.	Create the ND router and access ND router configuration mode.	router nd	Enter this command in context configuration mode.
5.	Optional. Configure global settings for the ND router by performing one or more of the following tasks, in any order:
	Specify the value for the Retrans Timer field.	ns-retry-interval
	Specify the value for the Preferred Lifetime field.	preferred-lifetime
	Configure RA messages.	ra	You can enter this command multiple times to configure different parameters.
	Specify the value for the Reachable Time field.	reachable-time
	Specify the value for the Valid Lifetime field.	valid-lifetime

To configure an interface for an ND router, perform the tasks described in Table 2; enter all commands in ND router interface configuration mode, unless otherwise noted.

*Table 2 Configure an ND Router Interface*
Step	Task	Root Command	Notes
1.	Select the context for the ND router.	context	Enter this command in global configuration mode.
2.	Select the ND router and access ND router configuration mode.	router nd	Enter this command in context configuration mode.
3.	Select an existing interface and access ND router interface configuration mode.	interface (ND)	Enter this command in ND router configuration mode.
4.	Optional. Configure the settings for this interface by performing one or more of the following tasks, in any order:		Unspecified settings default to the ND router global settings.
	Specify the value for the Retrans Timer field.	ns-retry-interval
	Specify the value for the Preferred Lifetime field.	preferred-lifetime
	Configure RA messages.	ra	You can enter this command multiple times to configure different parameters.
	Specify the value for the Reachable Time field.	reachable-time
	Specify the value for the Valid Lifetime field.	valid-lifetime
5.	Specify a static neighbor for this interface.	neighbor	You can enter this command multiple times.
6.	Configure a prefix to be advertised for this interface.	prefix	You can enter this command multiple times.

To monitor and troubleshoot ND features, perform the ND operations tasks described in Table 3. Enter the debug command in exec mode; enter the show commands in any mode.

*Table 3 ND Operations Tasks*
Task	Root Command
Enable the generation of debug messages for ND events.	debug nd
Display the current ND configuration.	interface (ND)
Display interface information for one or more ND router interfaces.	neighbor
Display neighbor information for one or more ND router interfaces.	show nd neighbor
Display prefix information for one or more ND router interfaces.	show nd prefix
Display static-neighbor information for one or more ND router interfaces.	show nd static-neighbor
Display global statistics for one or more ND router interfaces.	show nd statistics
Display summary information for the ND router global settings.	show nd summary

3 Configuration Examples

The following example shows how to configure an ND router in the local context and the int1 interface for the ND router:

! Create or select the context

[local]Redback(config)#context local 

! Create the interface with an IPv6 IP address

[local]Redback(config-ctx)#interface int1

[local]Redback(config-if)#ipv6 address 2005::1/64

[local]Redback(config-if)#exit

! Create the ND router; specify global parameters for all ND interfaces in this context

! The global settings override the default settings

[local]Redback(config-ctx)#router nd

[local]Redback(config-nd-if)#ns-retry-interval 100

[local]Redback(config-nd-if)#preferred-lifetime 43200

[local]Redback(config-nd)#ra interval 60

[local]Redback(config-nd)#ra lifetime 360

[local]Redback(config-nd-if)#reachable-time 1800

[local]Redback(config-nd-if)#valid-lifetime 43200

! Select an interface

[local]Redback(config-nd)#interface int1

! Specify interface-specific parameters; the interface settings override the global settings

[local]Redback(config-nd-if)#ns-retry-interval 20

[local]Redback(config-nd-if)#preferred-lifetime 2880

[local]Redback(config-nd-if)#ra suppress

[local]Redback(config-nd-if)#valid-lifetime 2880

! Specify one or more static neighbors for this interface

[local]Redback(config-nd-if)#neighbor 2006::1/64 00:30:88:00:0a:30

! Specify one or more prefixes and their parameters; the prefix settings override the interface settings

[local]Redback(config-nd-if)#prefix 2006::1/64 no-autoconfig no-onlink preferred-lifetime 360 valid-lifetime 360

[local]Redback(config-nd-if)#prefix 2007::/112 

[local]Redback(config-ctx)#

1	Overview
2	Configuration and Operations Tasks
3	Configuration Examples