Cisco ASR 9000 Series Aggregation Services Router Broadband Network Gateway Command Reference, Release 5.1.x
Neighbor Discovery Commands
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Neighbor Discovery Commands

Neighbor Discovery Commands

This module describes the Cisco IOS XR software commands used to configure the Neighbor Discovery Commands for Broadband Network Gateway (BNG) on the Cisco ASR 9000 Series Router. For details regarding the related configurations, refer to the Cisco ASR 9000 Series Aggregation Services Router Broadband Network Gateway Configuration Guide.

ipv6 nd dad attempts (BNG)

To configure the number of consecutive neighbor solicitation messages that are sent on an interface while duplicate address detection is performed on the unicast IPv6 addresses of the interface, use the ipv6 nd dad attempts command in an appropriate configuration mode. To return the number of messages to the default value, use the no form of this command.

ipv6 nd dad attempts value

no ipv6 nd dad attempts value

Syntax Description

value

Number of neighbor solicitation messages. Range is 0 to 600. Configuring a value of 0 disables duplicate address detection processing on the specified interface; a value of 1 configures a single transmission without follow-up transmissions.

Command Default

Duplicate address detection on unicast IPv6 addresses with the sending of one neighbor solicitation message is enabled. The default is one message.

Command Modes

Dynamic template configuration

Command History

Release

Modification

Release 3.7.2

This command was introduced.

Release 4.3.0

This command was supported in the dynamic template configuration mode for BNG.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Duplicate address detection verifies the uniqueness of new unicast IPv6 addresses before the addresses are assigned to interfaces (the new addresses remain in a tentative state while duplicate address detection is performed). Duplicate address detection uses neighbor solicitation messages to verify the uniqueness of unicast IPv6 addresses.

The DupAddrDetectTransmits node configuration variable (as specified in RFC 2462, IPv6 Stateless Address Autoconfiguration) is used to automatically determine the number of consecutive neighbor solicitation messages that are sent on an interface while duplicate address detection is performed on a tentative unicast IPv6 address.

The interval between the sending of duplicate address detection neighbor solicitation messages (the duplicate address detection timeout interval) is specified by the neighbor discovery-related variable RetransTimer (as specified in RFC 2461, Neighbor Discovery for IP Version 6 [IPv6]), which is used to determine the time between retransmissions of neighbor solicitation messages to a neighbor when the address is being resolved or when the reachability of a neighbor is being probed. This is the same management variable used to specify the interval for neighbor solicitation messages during address resolution and neighbor unreachability detection. Use the ipv6 nd ns-interval command to configure the interval between neighbor solicitation messages that are sent during duplicate address detection.

Duplicate address detection is suspended on interfaces that are administratively down. While an interface is administratively down, the unicast IPv6 addresses assigned to the interface are set to a pending state. Duplicate address detection is automatically restarted on an interface when the interface returns to being administratively up.

For BNG, ensure you run this command in the dynamic template configuration mode. To enter the dynamic template configuration mode, run dynamic-template command in the global configuration mode.


Note


An interface returning to administratively up restarts duplicate address detection for all of the unicast IPv6 addresses on the interface. While duplicate address detection is performed on the link-local address of an interface, the state for the other IPv6 addresses is still set to tentative. When duplicate address detection is completed on the link-local address, duplicate address detection is performed on the remaining IPv6 addresses.


When duplicate address detection identifies a duplicate address, the state of the address is set to duplicate and the address is not used. If the duplicate address is the link-local address of the interface, the processing of IPv6 packets is disabled on the interface and an error message similar to the following is issued:

ipv6_nd[145]: %IPV6_ND-3-ADDRESS_DUPLICATE : Duplicate address 111::1 has been detected 

If the duplicate address is a global address of the interface, the address is not used and an error message similar to the following is issued:

%IPV6-4-DUPLICATE: Duplicate address 3000::4 on GigabitEthernet

All configuration commands associated with the duplicate address remain as configured while the state of the address is set to duplicate.

If the link-local address for an interface changes, duplicate address detection is performed on the new link-local address and all of the other IPv6 address associated with the interface are regenerated (duplicate address detection is performed only on the new link-local address).

Task ID

Task ID

Operations

ipv6

read, write

config-services

read, write

Examples

This example shows how to display the state (tentative or duplicate) of the unicast IPv6 address on the dynamic template configuration mode:
RP/0/RSP0/CPU0:router(config)# dynamic-template type ppp p1
RP/0/RSP0/CPU0:router(config-dynamic-template-type)# ipv6 nd dad attempts 1

Related Commands

Command

Description

ipv6 nd ns-interval (BNG)

Configures the interval between IPv6 neighbor solicitation transmissions on an interface.

ipv6 nd framed-prefix-pool

To set the IPv6 Neighbor Discovery (ND) framed prefix pool, use the ipv6 nd framed-prefix-pool command in the dynamic template configuration mode. To disable the framed prefix pool configuration, use the no form of this command.

ipv6 nd framed-prefix-pool pool_name

no ipv6 nd framed-prefix-pool

Syntax Description

pool_name

Specifies the framed address pool name.

Command Default

None

Command Modes

Dynamic template configuration

Command History

Release

Modification

Release 4.3.0

This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

This value is included in all IPv6 router advertisements sent out from this interface. Very short intervals are not recommended in normal IPv6 operation. When a nondefault value is configured, the configured time is both advertised and used by the router itself.

To enter the dynamic template configuration mode, run dynamic-template command in the global configuration mode.

Task ID

Task ID

Operations

config-services

read, write

Examples

This example creates an IPv6 framed prefix pool in the dynamic template configuration mode:
RP/0/RSP0/CPU0:router(config)# dynamic-template type ppp p1
RP/0/RSP0/CPU0:router(config-dynamic-template-type)# ipv6 nd framed-prefix-pool pool1

ipv6 nd managed-config-flag (BNG)

To set the managed address configuration flag in IPv6 router advertisements, use the ipv6 nd managed-config-flag command in an appropriate configuration mode. To clear the flag from IPv6 router advertisements, use the no form of this command.

ipv6 nd managed-config-flag

no ipv6 nd managed-config-flag

Syntax Description

This command has no keywords or arguments.

Command Default

The managed address configuration flag is not set in IPv6 router advertisements.

Command Modes

Dynamic template configuration

Command History

Release

Modification

Release 3.7.2

This command was introduced.

Release 4.3.0

This command was supported in the dynamic template configuration mode for BNG.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Setting the managed address configuration flag in IPv6 router advertisements indicates to attached hosts whether they should use stateful autoconfiguration to obtain addresses. If the flag is set, the attached hosts should use stateful autoconfiguration to obtain addresses. If the flag is not set, the attached hosts should not use stateful autoconfiguration to obtain addresses.

Hosts may use stateful and stateless address autoconfiguration simultaneously.

For BNG, ensure you run this command in the dynamic template configuration mode. To enter the dynamic template configuration mode, run dynamic-template command in the global configuration mode.

Task ID

Task ID

Operations

ipv6

read, write

network

read, write

config-services

read, write

Examples

This example shows how to configure the managed address configuration flag in IPv6 router advertisements on dynamic template configuration mode:
RP/0/RSP0/CPU0:router(config)# dynamic-template type ppp p1
RP/0/RSP0/CPU0:router(config-dynamic-template-type)# ipv6 nd managed-config-flag

Related Commands

Command

Description

show ipv6 interface (BNG)

Displays the usability status of interfaces configured for IPv6.

ipv6 nd ns-interval (BNG)

To configure the interval between IPv6 neighbor solicitation retransmissions on an interface, use the ipv6 nd ns-interval command in an appropriate configuration mode. To restore the default interval, use the no form of this command.

ipv6 nd ns-interval milliseconds

no ipv6 nd ns-interval

Syntax Description

milliseconds

Interval (in milliseconds) between IPv6 neighbor solicit transmissions. Range is 1000 to 3600000.

Command Default

0 milliseconds (unspecified) is advertised in router advertisements, and the value 1000 is used for the neighbor discovery activity of the router itself.

Command Modes

Dynamic template configuration

Command History

Release

Modification

Release 3.7.2

This command was introduced.

Release 4.3.0

This command was supported in the dynamic template configuration mode for BNG.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

This value is included in all IPv6 router advertisements sent out from this interface. Very short intervals are not recommended in normal IPv6 operation. When a nondefault value is configured, the configured time is both advertised and used by the router itself.

For BNG, ensure you run this command in the dynamic template configuration mode. To enter the dynamic template configuration mode, run dynamic-template command in the global configuration mode.

Task ID

Task ID

Operations

ipv6

read, write

network

read, write

config-services

read, write

Examples

This example configures an IPv6 neighbor solicit transmission interval of 9000 milliseconds in the dynamic template configuration mode:
RP/0/RSP0/CPU0:router(config)# dynamic-template type ppp p1
RP/0/RSP0/CPU0:router(config-dynamic-template-type)# ipv6 nd ns-interval 9000

Related Commands

Command

Description

show ipv6 interface (BNG)

Displays the usability status of interfaces configured for IPv6.

ipv6 nd nud-enable

To enable the IPv6 neighbor un-reachability detection (NUD), use the ipv6 nd nud-enable command in the dynamic template configuration mode. To disable IPv6 NUD, use the no form of this command.

ipv6 nd nud-enable

no ipv6 nd nud-enable

Syntax Description

This command has no keywords or arguments.

Command Default

None

Command Modes

Dynamic template configuration

Command History

Release Modification

Release 4.3.0

This command was introduced.

Usage Guidelines

You must be in a user group associated with a task group that includes the proper task IDs. The command reference guides include the task IDs required for each command. If you suspect user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Task ID

Task ID Operation

config-services

read, write

Examples

This example shows how to enable IPv6 neighbor un-reachability detection in dynamic template configuration mode:

RP/0/RSP0/CPU0:router(config)# dynamic-template type ppp p1
RP/0/RSP0/CPU0:router(config-dynamic-template-type)# ipv6 nd nud-enable

ipv6 nd other-config-flag (BNG)

To set the other stateful configuration flag in IPv6 router advertisements, use the ipv6 nd other-config-flag command in an appropriate configuration mode. To clear the flag from IPv6 router advertisements, use the no form of this command.

ipv6 nd other-config-flag

no ipv6 nd other-config-flag

Syntax Description

This command has no keywords or arguments.

Command Default

The other stateful configuration flag is not set in IPv6 router advertisements.

Command Modes

Dynamic template configuration

Command History

Release

Modification

Release 3.7.2

This command was introduced.

Release 4.3.0

This command was supported in the dynamic template configuration mode for BNG.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

The setting of the other stateful configuration flag in IPv6 router advertisements indicates to attached hosts how they can obtain autoconfiguration information other than addresses. If the flag is set, the attached hosts should use stateful autoconfiguration to obtain the other (nonaddress) information.


Note


If the managed address configuration flag is set using the ipv6 nd managed-config-flag command, then an attached host can use stateful autoconfiguration to obtain the other (nonaddress) information regardless of the setting of the other stateful configuration flag.


For BNG, ensure you run this command in the dynamic template configuration mode. To enter the dynamic template configuration mode, run dynamic-template command in the global configuration mode.

Task ID

Task ID

Operations

ipv6

read, write

network

read, write

config-services

read, write

Examples

This example configures the “other stateful configuration” flag for IPv6 router advertisements in the dynamic template configuration mode:
RP/0/RSP0/CPU0:router(config)# dynamic-template type ppp p1
RP/0/RSP0/CPU0:router(config-dynamic-template-type)# ipv6 nd other-config-flag

Related Commands

Command

Description

ipv6 nd managed-config-flag (BNG)

Sets the managed address configuration flag in IPv6 router advertisements.

show ipv6 interface (BNG)

Displays the usability status of interfaces configured for IPv6.

ipv6 nd ra-initial

To set the IPv6 initial router advertisement count and interval, use the ipv6 nd ra-initial command in the dynamic template configuration mode. To restore the default interval, use the no form of this command.

ipv6 nd ra-initial count interval

no ipv6 nd ra-initial

Syntax Description

value

The initial count or the initial number of the IPv6 router advertisements. The value ranges from 0-32.

interval

The interval (in seconds) between IPv6 router advertisement counts. The value ranges from 4-1800.

Command Default

None

Command Modes

Dynamic template configuration

Command History

Release

Modification

Release 4.3.0

This command was supported in the dynamic template configuration mode for BNG.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

To enter the dynamic template configuration mode, run dynamic-template command in the global configuration mode.

Task ID

Task ID

Operations

config-services

read, write

Examples

This example configures an IPv6 router advertisement count of 5 and an interval of 201 seconds in the dynamic template configuration mode:
RP/0/RSP0/CPU0:router(config)# dynamic-template type ppp p1
RP/0/RSP0/CPU0:router(config-dynamic-template-type)# ipv6 nd ra-initial 5 201

Related Commands

Command

Description

ipv6 nd ra-interval (BNG)

Configures the interval between IPv6 router advertisement transmissions on an interface.  

ipv6 nd ra-interval (BNG)

To configure the interval between IPv6 router advertisement transmissions on an interface, use the ipv6 nd ra-interval command in an appropriate configuration mode. To restore the default interval, use the no form of this command.

ipv6 nd ra-interval seconds

no ipv6 nd ra-interval seconds

Syntax Description

seconds

The interval (in seconds) between IPv6 router advertisement transmissions.

Command Default

seconds : 200 seconds

Command Modes

Dynamic template configuration

Command History

Release

Modification

Release 3.7.2

This command was introduced.

Release 4.3.0

This command was supported in the dynamic template configuration mode for BNG.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

The interval between transmissions should be less than or equal to the IPv6 router advertisement lifetime if the router is configured as a default router by using the ipv6 nd ra-lifetime command. To prevent synchronization with other IPv6 nodes, randomly adjust the actual value used to within 20 percent of the specified value.

For BNG, ensure you run this command in the dynamic template configuration mode. To enter the dynamic template configuration mode, run dynamic-template command in the global configuration mode.

Task ID

Task ID

Operations

ipv6

read, write

network

read, write

config-services

read, write

Examples

This example configures an IPv6 router advertisement interval of 201 seconds in the dynamic template configuration mode:
RP/0/RSP0/CPU0:router(config)# dynamic-template type ppp p1
RP/0/RSP0/CPU0:router(config-dynamic-template-type)# ipv6 nd ra-interval 201

Related Commands

Command

Description

ipv6 nd ra-lifetime (BNG)

Configures the lifetime of an IPv6 router advertisement.

show ipv6 interface (BNG)

Displays the usability status of interfaces configured for IPv6.

ipv6 nd ra-lifetime (BNG)

To configure the router lifetime value in IPv6 router advertisements on an interface, use the ipv6 nd ra-lifetime command in an appropriate configuration mode. To restore the default lifetime, use the no form of this command.

ipv6 nd ra-lifetime seconds

no ipv6 nd ra-lifetime

Syntax Description

seconds

The validity (in seconds) of this router as a default router on this interface.

Command Default

seconds : 1800 seconds

Command Modes

Dynamic template configuration

Command History

Release

Modification

Release 3.7.2

This command was introduced.

Release 4.3.0

This command was supported in the dynamic template configuration mode for BNG.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

The router lifetime value is included in all IPv6 router advertisements sent out the interface. The value indicates the usefulness of the router as a default router on this interface. Setting the value to 0 indicates that the router should not be considered a default router on this interface. The router lifetime value can be set to a nonzero value to indicate that it should be considered a default router on this interface. The nonzero value for the router lifetime value should not be less than the router advertisement interval.

For BNG, ensure you run this command in the dynamic template configuration mode. To enter the dynamic template configuration mode, run dynamic-template command in the global configuration mode.

Task ID

Task ID

Operations

ipv6

read, write

network

read, write

config-services

read, write

Examples

This example configures an IPv6 router advertisement lifetime of 1801 seconds in the dynamic template configuration mode:
RP/0/RSP0/CPU0:router(config)# dynamic-template type ppp p1
RP/0/RSP0/CPU0:router(config-dynamic-template-type)# ipv6 nd ra-lifetime 1801

Related Commands

Command

Description

ipv6 nd ra-interval (BNG)

Configures the interval between IPv6 router advertisement transmissions on an interface.

show ipv6 interface (BNG)

Displays the usability status of interfaces configured for IPv6.

ipv6 nd ra-unicast

To enable the IPv6 unicast router advertisement (RA), use the ipv6 nd ra-unicast command in the dynamic template configuration mode. To disable IPv6 unicast RA, use the no form of this command.

ipv6 nd ra-unicast

no ipv6 nd ra-unicast

Syntax Description

This command has no keywords or arguments.

Command Default

None

Command Modes

Dynamic template configuration

Command History

Release Modification

Release 4.3.0

This command was introduced.

Usage Guidelines

You must be in a user group associated with a task group that includes the proper task IDs. The command reference guides include the task IDs required for each command. If you suspect user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Task ID

Task ID Operation

config-services

read, write

Examples

This example shows how to enable the IPv6 unicast router advertisement in dynamic template configuration mode:

RP/0/RSP0/CPU0:router(config)# dynamic-template type ppp p1
RP/0/RSP0/CPU0:router(config-dynamic-template-type)# ipv6 nd ra-unicast

Related Commands

Command

Description

dynamic-template

Groups a set of configuration items that can be applied to a group of subscribers.  

ipv6 nd reachable-time (BNG)

To configure the amount of time that a remote IPv6 node is considered reachable after some reachability confirmation event has occurred, use the ipv6 nd reachable-time command in an appropriate configuration mode. To restore the default time, use the no form of this command.

ipv6 nd reachable-time milliseconds

no ipv6 nd reachable-time

Syntax Description

milliseconds

The amount of time (in milliseconds) that a remote IPv6 node is considered reachable. The range is from 0 to 3600000.

Command Default

0 milliseconds (unspecified) is advertised in router advertisements and 30000 (30 seconds) is used for the neighbor discovery activity of the router itself.

Command Modes

Dynamic template configuration

Command History

Release

Modification

Release 3.7.2

This command was introduced.

Release 4.3.0

This command was supported in the dynamic template configuration mode for BNG.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

The configured time enables the router to detect unavailable neighbors. Shorter configured times enable the router to detect unavailable neighbors more quickly; however, shorter times consume more IPv6 network bandwidth and processing resources in all IPv6 network devices. Very short configured times are not recommended in normal IPv6 operation.

The configured time is included in all router advertisements sent out of an interface so that nodes on the same link use the same time value. A value of 0 indicates that the configured time is unspecified by this router.

For BNG, ensure you run this command in the dynamic template configuration mode. To enter the dynamic template configuration mode, run dynamic-template command in the global configuration mode.

Task ID

Task ID

Operations

ipv6

read, write

network

read, write

config-services

read, write

Examples

This example shows how to configure an IPv6 reachable time of 1,700,000 milliseconds in the dynamic template configuration mode:
RP/0/RSP0/CPU0:router(config)# dynamic-template type ppp p1
RP/0/RSP0/CPU0:router(config-dynamic-template-type)# ipv6 nd reachable-time 1700000

Related Commands

Command

Description

show ipv6 interface (BNG)

Displays the usability status of interfaces configured for IPv6.

ipv6 nd suppress-cache-learning

To suppress cache learning for IPv6 neighbor discovery, use the ipv6 nd suppress-cache-learning command in the dynamic template configuration mode. To disable cache learning suppress, use the no form of this command.

ipv6 nd suppress-cache-learning

no ipv6 nd suppress-cache-learning

Syntax Description

This command has no keywords or arguments.

Command Default

None

Command Modes

Dynamic template configuration

Command History

Release Modification

Release 4.3.0

This command was introduced.

Usage Guidelines

You must be in a user group associated with a task group that includes the proper task IDs. The command reference guides include the task IDs required for each command. If you suspect user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Task ID

Task ID Operation

config-services

read, write

Examples

This example shows how to suppress cache learning for IPv6 neighbor discovery in dynamic template configuration mode:

RP/0/RSP0/CPU0:router(config)# dynamic-template type ppp p1
RP/0/RSP0/CPU0:router(config-dynamic-template-type)# ipv6 nd suppress-cache-learning

ipv6 nd suppress-ra (BNG)

To suppress IPv6 router advertisement transmissions on a LAN interface, use the ipv6 nd suppress-ra command in an appropriate configuration mode. To reenable the sending of IPv6 router advertisement transmissions on a LAN interface, use the no form of this command.

ipv6 nd suppress-ra

no ipv6 nd suppress-ra

Syntax Description

This command has no keywords or arguments.

Command Default

IPv6 router advertisements are automatically sent on other types of interlaces if IPv6 unicast routing is enabled on the interfaces. IPv6 router advertisements are not sent on other types of interfaces.

Command Modes

Dynamic template configuration

Command History

Release

Modification

Release 3.7.2

This command was introduced.

Release 4.3.0

This command was supported in the dynamic template configuration mode for BNG.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Use the no ipv6 nd suppress-ra command to enable the sending of IPv6 router advertisement transmissions on non-LAN interface types (for example, serial or tunnel interfaces).

For BNG, ensure you run this command in the dynamic template configuration mode. To enter the dynamic template configuration mode, run dynamic-template command in the global configuration mode.

Task ID

Task ID

Operations

ipv6

read, write

network

read, write

config-services

read, write

Examples

This example shows how to suppress IPv6 router advertisements in the dynamic template configuration mode:
RP/0/RSP0/CPU0:router(config)# dynamic-template type ppp p1
RP/0/RSP0/CPU0:router(config-dynamic-template-type)# ipv6 nd suppress-ra

Related Commands

Command

Description

show ipv6 interface (BNG)

Displays the usability status of interfaces configured for IPv6.