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From: ravi@ubc.CSNET.UUCP
Newsgroups: comp.protocols.tcp-ip
Subject: Re: Automatic IP address assignment
Message-ID: <454*ravi@cs.ubc.cdn>
Date: Sat, 13-Jun-87 20:12:04 EDT
Article-I.D.: cs.454*ravi
Posted: Sat Jun 13 20:12:04 1987
Date-Received: Sun, 14-Jun-87 05:38:15 EDT
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Hi,

	Dynamic address assignment has been employed in some experimental
distributed operating systems. Though the host addresses thus assigned are
not IP addresses, the techniques may be adapted to assigning IP addresses
dynamically. For example, the V distributed operating system developed at
the Stanford University uses a dynamic address assignment protocol similar
to that of your "defended addresses". The system has a large pool of
assignable addresses from which a booting machine picks up one (based on
random number generation) and solicits any objections to its usage of the
address. A machine that may already use the address "defends" the address by
raising an objection. If no objection is received by the booting machine, it
starts using the address. Otherwise, it picks up another one and tries
again. We at the University of British Columbia have designed a variant of
the protocol to make sure that the addresses are non-reusable in the "near
future". Both schemes are distributed and do not suffer from single-point
failures. Our protocol additionally guarantees non-reusability of addresses
if reliability is a concern.

	We have a technical report which describes the implications of such
dynamic bindings between host and network addresses, how cached bindings are
invalidated/corrected in a dynamic environment such as when machines fail
and come up later, resolving multiply assigned addresses (because of network
failures), etc. The report is awaiting publication in "Computer Networks and
the ISDN" journal. If any one wants the report, send me an e-mail.

				Ravindran
				Dept. of Computer Science,
				Univ. of British Columbia,
				Vancouver B.C. V6T 1W5, Canada.
				Ph: (604) 228-5485