Neighbor Discovery Configuration

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Table of Contents

Table of Contents

Chapter 1 Neighbor Discovery Configuration..............................................................................................1
1.1 Neighbor Discovery Overview.........................................................................................................1

1.1.1 Address Resolution............................................................................................................... 2

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ND Configuration

Chapter 1 Neighbor Discovery Configuration

1.1 Neighbor Discovery Overview

A node (host and router) uses ND (Neighbor Discovery protocol) to determine the link-layer

addresses of the connected neighbors and to delete invalid cache rapidly. The host also uses

the neighbor to discover the packet-forwarding neighboring routers. Additionally, the node

uses the ND mechanism to positively trace which neighbors are reachable or unreachable and

to test the changed link-layer address. When a router or the path to a router has trouble, the

host positively looks for another working router or another path.

IPv6 ND corresponds to IPv4 ARP, ICMP router discovery and ICMP redirect.

ND supports the following link types: P2P, multicast, NBMA, shared media, changeable MTU

and asymmetric reachability. The ND mechanism has the following functions:

(1) To discover routers: how the host to locate the routers on the connected links.

(2) To discover prefixes: how the host to find a group of address prefixes, defining which

destinations are on-link on the connected links.

(3) To discover parameters: how the node to know the link-related or network-related

parameters of the transmission interface.

(4) To automatically set addresses: how the node to set the address of an interface

automatically.

(5) Address solution: When the IP of a destination is given, how a node determines the

link-layer address of the on-link destination.

(6) To determine the next hop: it is an algorithm to map the IP address of a destination to the

neighboring IP. The next hop can be a router or destination.

(7) To test unreachable neighbors: how a node to determine unreachable neighbors; if

neighbor is a router, the default router can be used. If the neighbor is both router and host, it

needs address resolution.

(8) To test repeated address: how a node to determine whether a to-be-used address is not

used by another node.

(9) Redirect: how a router to notify the host of the best next hop.

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ND Configuration

1.1.1 Address Resolution

Address resolution is a procedure of resolving the link-layer address through node’s IP. Packet

exchange is realized through ND request and ND notification.

 Configuring a static ND cache

In most cases, dynamic address resolution is used and static ND cache

configuration is not needed. If necessary, you can set static ND cache in global

mode and the system will use it to translate IP into the link-layer address. The

following table shows how to set a static-IP-to-link-layer-address mapping.

Run the following relative command in global mode:
Command Purpose

ipv6 neighbor ipv6address vlan vlanid Sets a static ND cache and translates IPv6
hardware-address address into a link-layer address.

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