Date: Mon, 29 Jul 2002 12:53:16 +0200
From: "Nils Agne Nordbotten" <[EMAIL PROTECTED]>
Message-ID: <014001c236ee$24fecd30$8cb9d8c1@nansb>
| While this is simple in traditional LANs I'm worried about the consequences
| in networks like Bluetooth scatternets where devices in power saving modes
| will have to be waked up.
If the hardware is rational (a topic about which I know nothing at all,
it might not be, but perhaps if pressed, it will improve) the devices
won't need to wake up. Remember ND (including DAD) is not ARP, packets
aren't broadcast, they're multicast, and to a multicast address which
will normally only have as members of the same multicast group nodes
sharing the same IID. If you're one of the believers of "no IID sharing"
then doing DAD instead of DIIDD won't change that, and usually, there will
be no other members of the group than the node which is doing DAD.
The DAD packets consume an (insignificant) amount of bandwidth, but
when all is working properly, go nowhere at all.
| I also imagine there easily will be partitions in
| such networks, and that DAD therefore will provide little assurance.
If partitions are common (aside: why would anyone use a link where the
chances of not being able to talk to any other random node on the link,
like the router, or fileserver, ... are not negligible??) then sure,
DAD won't provide a lot or protection, but DIID would provide even less,
as less probes are done. At least with DAD, you have a better chance of
some of your addresses being detected as duplicates, which will start waving
the red flags.
| Instead address uniqueness could be assured from EUIs.
If EUIs are being used to form the addresses, then duplicates should
be very very rare, and all DAD really achieves in the usual case is a little
bandwidth consumption and a small delay. But it does no harm either.
kre
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