Users Guide

Link-local Addresses
Link-local addresses, starting with fe80:, are assigned only in the local link area.
The addresses are generated automatically by the operating system's IP layer for each network interface. This
provides instant automatic network connectivity for any IPv6 host and means that if several hosts connect to
a common hub or switch, they have an instant communication path via their link-local IPv6 address.
Link-local addresses cannot be routed to the public Internet.
Static and Dynamic Addressing
Static IPv6 addresses are manually assigned to a computer by an administrator.
Dynamic IPv6 addresses are assigned either randomly or by a server using dynamic host configuration
protocol (DHCP). Even though IPv6 addresses assigned using DHCP may stay the same for long periods of
time, they can change. In some cases, a network administrator may implement dynamically assigned static
IPv6 addresses. In this case, a DHCP server is used, but it is specifically configured to always assign the same
IPv6 address to a particular computer, and never to assign that IP address to another computer. This allows
static IPv6 addresses to be configured in one place, without having to specifically configure each computer
on the network in a different way.
In IPv6, every interface, whether using static or dynamic address assignments, also receives a local-link
address automatically in the fe80::/64 subnet.
Implementing IPv6 with Dell
Networking OS
Dell Networking OS supports both IPv4 and IPv6 and both may be used simultaneously in your system.
ICMPv6
ICMP for IPv6 combines the roles of ICMP, IGMP and ARP in IPv4.
Like IPv4, it provides functions for reporting delivery and forwarding errors, and provides a simple echo
service for troubleshooting. The Dell Networking OS implementation of ICMPv6 is based on RFC 2463.
Generally, ICMPv6 uses two message types:
• Error reporting messages indicate when the forwarding or delivery of the packet failed at the destination
or intermediate node. These messages include Destination Unreachable, Packet Too Big, Time
Exceeded and Parameter Problem messages.
• Informational messages provide diagnostic functions and additional host functions, such as Neighbor
Discovery and Multicast Listener Discovery. These messages also include Echo Request and Echo Reply
messages.
The Dell Networking OS ping and traceroute commands extend to support IPv6 addresses. These
commands use ICMPv6 Type-2 messages.
IPv6 Routing 546