Users Guide
In place 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 conguring 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 eciency.
Figure 56. NDP Router Redirect
IPv6 Neighbor Discovery of MTU Packets
You can set the MTU advertised through the RA packets to incoming routers, without altering the actual MTU setting on the interface.
The ipv6 nd mtu command sets the value advertised to routers. It does not set the actual MTU rate. For example, if you set ipv6 nd
mtu
to 1280, the interface still passes 1500-byte packets, if that is what is set with the mtu command.
Conguring the IPv6 Recursive DNS Server
You can congure up to four Recursive DNS Server (RDNSS) addresses to be distributed via IPv6 router advertisements to an IPv6 device,
using the ipv6 nd dns-server ipv6-RDNSS-address {lifetime | infinite} command in INTERFACE CONFIG mode.
The lifetime parameter congures the amount of time the IPv6 host can use the IPv6 RDNSS address for name resolution. The lifetime
range is 0 to 4294967295 seconds. When the maximum lifetime value, 4294967295, or the infinite keyword is specied, the
lifetime to use the RDNSS address does not expire. A value of 0 indicates to the host that the RDNSS address should not be used. You
must specify a lifetime using the lifetime or innite parameter.
The DNS server address does not allow the following:
• link local addresses
404
IPv6 Routing