Administrator 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 conguration 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 specically congured 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 congured in one place, without having to specically congure each computer on the network in a dierent 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.
Path MTU Discovery
Path MTU (Maximum Transmission Unit) denes the largest packet size that can traverse a transmission path without suering
fragmentation.
Path MTU for IPv6 uses ICMPv6 Type-2 messages to discover the largest MTU along the path from source to destination and avoid the
need to fragment the packet.
IPv6 Routing
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