Reference Guide

IPv6 Routing
Internet protocol version 6 (IPv6) routing is the successor to IPv4. Due to the rapid growth in internet users and IP addresses,
IPv4 is reaching its maximum usage. IPv6 will eventually replace IPv4 usage to allow for the constant expansion.
This chapter provides a brief description of the differences between IPv4 and IPv6, and the Dell Networking support of IPv6.
This chapter is not intended to be a comprehensive description of IPv6.
NOTE: The IPv6 basic commands are supported on all platforms. However, not all features are supported on all platforms,
nor for all releases. To determine the Dell Networking OS version supporting specific features and platforms, refer to
Implementing IPv6 with Dell Networking OS.
Topics:
• Protocol Overview
• IPv6 Implementation on the Dell Networking OS
• Configuring the LPM Table for IPv6 Extended Prefixes
• ICMPv6
• Path MTU Discovery
• IPv6 Neighbor Discovery
• Secure Shell (SSH) Over an IPv6 Transport
• Configuration Tasks for IPv6
Protocol Overview
IPv6 is an evolution of IPv4. IPv6 is generally installed as an upgrade in devices and operating systems. Most new devices and
operating systems support both IPv4 and IPv6.
Some key changes in IPv6 are:
● Extended address space
● Stateless autoconfiguration
● Header format simplification
● Improved support for options and extensions
Extended Address Space
The address format is extended from 32 bits to 128 bits. This not only provides room for all anticipated needs, it allows for the
use of a hierarchical address space structure to optimize global addressing.
Stateless Autoconfiguration
When a booting device comes up in IPv6 and asks for its network prefix, the device can get the prefix (or prefixes) from an IPv6
router on its link. It can then autoconfigure one or more global IPv6 addresses by using either the MAC address or a private
random number to build its unique IPv6 address.
Stateless autoconfiguration uses three mechanisms for IPv6 address configuration:
● Prefix Advertisement — Routers use “Router Advertisement” messages to announce the network prefix. Hosts then use
their interface-identifier MAC address to generate their own valid IPv6 address.
● Duplicate Address Detection (DAD) — Before configuring its IPv6 address, an IPv6 host node device checks whether
that address is used anywhere on the network using this mechanism.
● Prefix Renumbering — Useful in transparent renumbering of hosts in the network when an organization changes its
service provider.
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