Administrator Guide

The recommended MTU for IPv6 is 1280. Greater MTU settings increase processing eciency because each packet carries more data
while protocol overheads (for example, headers) or underlying per-packet delays remain xed.
Figure 56. Path MTU Discovery Process
IPv6 Neighbor Discovery
NDP is a top-level protocol for neighbor discovery on an IPv6 network.
In lieu of address resolution protocol (ARP), NDP uses “Neighbor Solicitation” and “Neighbor Advertisement” ICMPv6 messages for
determining relationships between neighboring nodes. Using these messages, an IPv6 device learns the link-layer addresses for neighbors
known to reside on attached links, quickly purging cached values that become invalid.
NOTE
: If a neighboring node does not have an IPv6 address assigned, it must be manually pinged to allow the IPv6 device to
determine the relationship of the neighboring node.
NOTE: To avoid problems with network discovery, Dell Networking recommends conguring the static route last or assigning an
IPv6 address to the interface and assigning an address to the peer (the forwarding router’s address) less than 10 seconds apart.
With ARP, each node broadcasts ARP requests on the entire link. This approach causes unnecessary processing by uninterested nodes.
With NDP, each node sends a request only to the intended destination via a multicast address with the unicast address used as the last 24
bits. Other hosts on the link do not participate in the process, greatly increasing network bandwidth eciency.
456
IPv6 Routing