Product Documentation

Neighbor Discovery

Neighbor discovery (ND) is one of the most important protocols of IPv6. It is a message-based protocol that combines the functionality of the Address Resolution Protocol (ARP), Internet Control Message Protocol (ICMP), and Router Discovery. ND allows nodes to advertise their link layer addresses and obtain the MAC addresses or link layer addresses of the neighboring nodes. This process is performed by the Neighbor Discovery protocol (ND6).

Neighbor discovery can perform the following functions:

  • Router Discovery: Enables a host to discover the local routers on an attached link and automatically configure a default router.
  • Prefix Discovery: Enables the host to discover the network prefixes for local destinations.

    Note: The Citrix ADC appliance does not support Prefix Discovery.

  • Parameter Discovery: Enables a host to discover additional operating parameters, such as MTU and the default hop limit for outbound traffic.
  • Address Autoconfiguration: Enables hosts to automatically configure IP addresses for interfaces both with and without stateful address configuration services such as DHCPv6. The Citrix ADC does not support Address Autoconfiguration for Global IPv6 addresses.
  • Address Resolution: Equivalent to ARP in IPv4, enables a node to resolve a neighboring node’s IPv6 address to its link-layer address.
  • Neighbor Unreachability Detection: Enables a node to determine the reachability state of a neighbor.
  • Duplicate Address Detection: Enables a node to determine whether an NSIP address is already in use by a neighboring node.
  • Redirect: Equivalent to the IPv4 ICMP Redirect message, enables a router to redirect the host to a better first-hop IPv6 address to reach a destination.

Note: The Citrix ADC appliance does not support IPv6 Redirect.

Configuration Steps

Configuring neighbor discovery consists of the following tasks:

  • Adding IPv6 neighbors
  • (Optional) Removing IPv6 neighbors

CLI procedures

To add an IPv6 neighbor by using the CLI:

At the command prompt, type:

  • add nd6 <neighbor> <mac> <ifnum> [-vlan <integer>]
  • sh nd6

Example:

> add nd6 2001::1 00:04:23:be:3c:06 1/1 –vlan 1
 Done

> show nd6
   Neighbor                 MAC-Address(Vlan, Interface)       State        TIME
   --------                 ----------------------------       -----      --------
1) ::1                      00:d0:68:0b:58:da(   1,  LO/1)   REACHABLE     PERMANENT
2) fe80::2d0:68ff:fe0b:58da 00:d0:68:0b:58:da(   1,  LO/1)   REACHABLE     PERMANENT
3) 2001::1                  00:04:23:be:3c:06(   1,   1/1)   REACHABLE       STATIC
 Done

To remove a neighbor discovery entry by using the CLI:

At the command prompt, type:

  • rm nd6 <Neighbor> -vlan <VLANID>

Example:


 rm nd6 3ffe:100:100::1 -vlan 1

To remove all neighbor discovery entries by using the CLI:

At the command prompt, type:

  • clear nd6

GUI procedures

To add an IPv6 neighbor by using the GUI:

Navigate to System > Network > IPv6 Neighbors, and add a new IPv6 neighbor.

To remove a neighbor discovery entry by using the GUI:

Navigate to System > Network > IPv6 Neighbors, delete the IPv6 neighbor.

To remove all neighbor discovery entries by using the GUI:

Navigate to System > Network > IPv6 Neighbors, and click Clear.

Neighbor Discovery

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