Setup Guide

For example, 2001:0db8:1234::/48 stands for the network with addresses 2001:0db8:1234:0000:0000:0000:0000:0000 through
2001:0db8:1234:ffff:ffff:ffff:ffff:ffff.
Link-local Addresses
Link-local addresses, starting with fe80:, are assigned only in the local link area.
The addresses are generated usually 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 EMC Networking OS
Dell EMC 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 EMC Networking OS implementation of ICMPv6 is based on RFC
4443.
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 EMC Networking OS ping and traceroute commands extend to support IPv6 addresses. These commands use ICMPv6
Type-2 messages.
Path MTU discovery
The size of the packet that can be sent across each hop in the network path without being fragmented is called the path maximum
transmission unit (PMTU). The PMTU value might differ for the same route between two devices, mainly over a public network,
depending on the network load and speed, and it is not a consistent value. The MTU size can also be different for various types of traffic
sent from one host to the same endpoint.
Path MTU discovery (PMTD) identifies the path MTU value between the sender and the receiver, and uses the determined value to
transmit the packets across the network. Path MTU, in accordance with RFC 1981, defines the largest packet size that can traverse a
transmission path without suffering 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. The recommended MTU for IPv6 is 1280. Greater MTU
settings increase the processing efficiency because each packet carries more data while protocol overheads (for example, headers) or
underlying per-packet delays remain fixed.
IPv6 Routing
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