[dhcwg] Re: [mobile-ip] IPv4 Address Conflict Detection

Gerald Maguire <maguire@it.kth.se> Tue, 05 February 2002 06:37 UTC

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From: Gerald Maguire <maguire@it.kth.se>
To: mobile-ip@sunroof.eng.sun.com
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In-reply-to: <200202041944.g14JiY026372@scv2.apple.com> (message from Stuart Cheshire on Mon, 4 Feb 2002 11:44:34 -0800)
References: <200202041944.g14JiY026372@scv2.apple.com>
Subject: [dhcwg] Re: [mobile-ip] IPv4 Address Conflict Detection
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I think the idea of probing and waiting _before_ using an address is
completely wrong. Since it involves waiting for something _not_ to
happen. The better approach is to detect the conflict -- if there is
one. See:
@misc{ vatn-effect,
         author = "Jon-Olov Vatn and Gerald Q. Maguire Jr.",
	  title = "The effect of using co-located care-of addresses on macro
	            handover latency",
            url = "http://citeseer.nj.nec.com/264743.html" }

ftp://ftp.it.kth.se/Reports/ts/1998/nts14-coloc.pdf

This paper shows that the DHCP server can be doing testing of
addresses in advance and this significantly reduce the time required
to assign and address. This is critical if you are going to give a
mobile device an IP address on a new segment when it arrive and avoid
having to drop packets for it (for example from an audio stream).

See also:

Jon-Olov Vatn, "Long Random Wait Times for Getting a Care-of Address
are a Danger to Mobile Multimedia", 1999 IEEE International Workshop
on Mobile Multimedia Communications (MoMuC'99), 15-17 November 1999,
San Diego, CA USA.
   http://www.it.kth.se/~vatn/research/momuc-copyright.pdf

For his licentiate thesis which includes the above and more see:
  http://www.it.kth.se/~vatn/mac/lic_prop.fm5.ps

Chip

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