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    Configuring Neighbor Discovery

    This topic includes the following tasks:

    Before You Configure Neighbor Discovery

    Before you configure Neighbor Discovery, you must configure IPv6. For information about configuring IPv6, see Managing IPv6 Interfaces.

    Configuring Ethernet interfaces to function with IPv6 requires Neighbor Discovery configuration for the interface.

    Note: IPv6 Neighbor Discovery is fully supported when configured on broadcast interfaces. IPv6 neighbor discovery supports only router advertisement characteristics when configured on PPP interfaces.

    Configuring Neighbor Discovery

    To configure Neighbor Discovery:

    1. Access an IPv6 interface.
      host1(config)#interface fastEthernet 3/0 host1(config-if)#
    2. Configure the current IPv6 interface to send neighbor solicitations and to respond with neighbor advertisements.
      host1(config-if)#ipv6 nd

      Note: This command is redundant when configuring Neighbor Discovery over Ethernet, because router advertisements are automatically sent on Ethernet interfaces. However, unless explicitly enabled, IPv6 router advertisements are not sent on other types of interfaces.

    3. (Optional) Configure the interface to retry sending neighbor solicitations using a specified interval.
      host1(config-if)#ipv6 nd ns-interval 500
    4. (Optional) Configure the interface to assume that a neighbor is reachable for a specified time after a reachable confirmation event.
      host1(config-if)#ipv6 nd reachable-time 30000
    5. (Optional) Configure the interface to suppress router advertisements, as well as replies to router solicitations.
      host1(config-if)#ipv6 nd suppress-ra
    6. (Optional) Configure the interface to suppresses the source link-layer option in IPv6 router advertisement transmissions. This action forces neighbors to solicit the router link layer explicitly, and may prove necessary when enabling inbound load sharing across multiple link-layer addresses.
      host1(config-if)#ipv6 nd suppress-ra-source-link-layer
    7. (Optional) Configure the interface to send router advertisements at a specified interval.
      host1(config-if)#ipv6 nd ra-interval 500
    8. (Optional) Configure the router advertisement lifetime in seconds.
      host1(config-if)#ipv6 nd ra-lifetime 900
    9. (Optional) Configure the router advertisement to list a specified prefix, for a valid lifetime and preferred lifetime. The following example also advertises the prefix as reachable on link and that the router can use it as part of the stateless address configuration.
      host1(config-if)#ipv6 nd prefix-advertisement 2002:1::/64 60000 45000 onlink autoconfig
    10. (Optional) Configure the router advertisement to contain the “managed address configuration” flag.
      host1(config-if)#ipv6 nd managed-config-flag
    11. (Optional) Configure the router advertisement to contain the “other stateful configuration” flag.
      host1(config-if)#ipv6 nd other-config-flag
    12. (Optional) Enable active solicitations.
      host1(config-if)#ipv6 nd active-solicitations

    Using IPv6 Profiles and RADIUS to Configure Neighbor Discovery Route Advertisements

    In addition to the CLI-based configuration of Neighbor Discovery, you can also use IPv6 profiles to configure Neighbor Discovery route advertisements for dynamically configured interfaces. You can also use RADIUS to configure the prefix in Neighbor Discovery route advertisements for dynamically configured interfaces.

    When you configure either a profile-based or RADIUS-based Neighbor Discovery router advertisement, the following considerations apply:

    • You can advertise one IPv6 prefix per interface.
    • The router advertisement must have a prefix length of 64. For the Ipv6-NdRa-Prefix attribute, the prefix length is in the following format, in which 0040 indicates the prefix length of 64.
      0x 0040 xxxx xxxx xxxx xxxx

      Note: If both an IPv6 profile and RADIUS are configured for Neighbor Discovery router advertisement, the prefix value returned in RADIUS VSA 26-129 takes precedence over the prefix specified in the IPv6 profile configuration.

    In addition to the CLI-based configuration of Neighbor Discovery, you can also use the following tasks:

    IPv6 Profile-Based Configuration

    The JunosE Software enables you to use profiles to dynamically configure IPv6 interfaces. When you create an IPv6 profile, you can also include Neighbor Discovery route advertisement characteristics, which are then configured on the dynamically-created IPv6 interfaces.

    You can include the following commands in IPv6 profiles to configure Neighbor Discovery route advertisement characteristics.

    Command

    Description

    ipv6 nd

    Enables Neighbor Discovery on an interface

    ipv6 nd managed-config-flag

    Sets the “ managed address configuration” flag in IPv6 router advertisements

    ipv6 nd other-config-flag

    Sets the “ other stateful configuration” flag in IPv6 router advertisements

    ipv6 nd prefix-advertisement

    Specifies which IPv6 prefixes are included in IPv6 router advertisements

    ipv6 nd ra-interval

    Configures the interval between IPv6 router advertisements

    ipv6 nd ra-lifetime

    Configures the router advertisement lifetime

    ipv6 nd reachable-time

    Configures the amount of time the router can reach an IPv6 node after a reachability confirmation event occurs

    ipv6 nd suppress-ra

    Disables router advertisement transmissions

    For additional information about using IPv6 profiles to configure dynamic interfaces, see IPv6 Profiles and JunosE Link Layer Configuration Guide.

    RADIUS-Based Configuration

    You can use RADIUS attribute Ipv6-NdRa-Prefix (VSA 26-129) to configure the prefix used in IPv6 Neighbor Discovery route advertisements. RADIUS then includes the VSA in Access-Accept messages. For information about the Ipv6-NdRa-Prefix RADIUS attribute, see Configuring RADIUS Attributes and RADIUS Attribute Descriptions in the JunosE Broadband Access Configuration Guide.

    Published: 2014-08-13