the same IPv6 address to a particular computer, and never to assign that IP address to another computer. This allows static IPv6 addressesto 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 thefe80::/64 subnet.Implementing IPv6 with Dell Networking OSDell Networking OS supports both IPv4 and IPv6 and both may be used simultaneously in your system.ICMPv6ICMP for IPv6 combines the roles of ICMP, IGMP and ARP in IPv4. Like IPv4, it provides functions for reporting delivery and forwardingerrors, and provides a simple echo service for troubleshooting. The Dell 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. Thesemessages 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 ListenerDiscovery. 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-2messages.Path MTU DiscoveryPath MTU, in accordance with RFC 1981, defines the largest packet size that can traverse a transmission path without sufferingfragmentation. Path MTU for IPv6 uses ICMPv6 Type-2 messages to discover the largest MTU along the path from source to destinationand avoid the need to fragment the packet.The recommended MTU for IPv6 is 1280. Greater MTU settings increase processing efficiency because each packet carries more datawhile protocol overheads (for example, headers) or underlying per-packet delays remain fixed.Figure 57. Path MTU Discovery Process436 IPv6 Routing
