On Wed, 06 Jun 2012 17:17:37 -0400, Karl Auer <kauer@biplane.com.au> wrote:
a) DAD only happens when an IPv6 node is starting up. ARP happens whenever a node needs to talk to another node that it hasn't seen in while.
DAD is a special case of ND. It happens every time the system selects an address. (i.e. startup with non-SLAAC address, and when privacy extensions generates an address.)
b) DAD only goes to solicited node multicast addresses, i.e., only to those nodes that share the same last 24 bits as the target address. ARP goes to every node on the link (broadcast).
This assumes a network of devices that do multicast filtering, correctly. This is not a good assumption even in large enterprises. Common residential gear usually doesn't understand multicast at all. (unless you're a uverse tv customer using ethernet and paid close attention to your hardware.)
c) Similarly, ND (the direct equivalent of ARP) goes only to solicited node multicast addresses, ARP goes to every node on the link.
Effectively the same as broadcast in the IPv6 world. If everyone is running IPv6, then everyone will see the packet. (things not running ipv6 can filter it out, but odds are it'll be put on the cable.)
So I'm not sure how DAD traffic would exceed ARP traffic.
I wouldn't expect it to. Looking at the output of my 3745, it fires 3 ND's at startup and is then silent. (TWC has no IPv6 on my node, but v4 ARP broadcasts amount to ~16K/s) --Ricky