Subject: Definition of terms

From: Lee Chee Jwai <[email-masked]>
Date: Tue, 27 May 1997 08:39:12 +0800 (SGT)

I received a total of three replies to my query on the differences between
"packet radio network", "ad hoc network" (without hyphen!) and "mobile
mesh network". 

Most agree (2/3) that these are all terms that at various times have been
used by various groups of people to refer to the same thing.  There is no
single well-accepted term for this type of network. 

Scott Corson from UMD proposed a more generic and descriptive term:

	mobile multihop wireless network

Below is one way to define such a network (extracted from the paper
"Protocols for Adaptive Wireless and Mobile Networking", by David Johnson
and David Maltz, in the February 1996 issue of IEEE Personal
Communications): 

  At times, no infrastructure such as the Internet may be available for
  use by a group of wireless mobile hosts, or the use of an available
  network infrastructure may be undesirable due to reasons such as cost or
  convenience.  Examples of such situations include disaster recovery
  personnel or military troops in cases in which the normal infrastructure
  is either unavailable (such as in a remote area) or destroyed (such as
  after an earthquake); other examples include business associates wishing
  to share files in an airport terminal, or a class of students needing to
  interact during a lecture.  If each mobile host wishing to communicate
  is equipped with a wireless local area network interface, the group of
  mobile hosts may form an ad hoc network.  An ad hoc network is a
  temporary network, operating without the aid of any established
  infrastructure or centralized administration.

  In an ad hoc network, some hosts wishing to communicate may be outside
  of wireless transmission range of each other, but may be able to
  communicate if other hosts in the network are willing to forward packets
  for them.  An ad hoc network in general requires some form of routing
  protocol in order to dynamically find multihop paths through the
  network, and in order to adapt to new routes as the mobile hosts in the
  network move.  Furthermore, the protocol must be able to operate
  correctly in spite of the varying propagation characteristics of each
  mobile host's wireless transmissions, for example due to changes in
  sources of interference in the vicinity of each mobile host.

Rex Buddenberg from NPS however pointed out something interesting. He
highlighted that there's a distinction between "packet radio network" and
the other two. The former tends to focus on a particular segment/network
and the latter have to do with internetworks where the router connectivity
changes frequently and unpredictably.  While the terms do not specifically
denote radio networks, those are the kind that exhibit the dynamism that
drives the perceptions of need agile router configs. 

Comments?

_____________________________________________________________________
Cheejwai LEE 		   	 		
DSO National Laboratories	   Tel  : (65) 3732045
20 Science Park Drive     	   Fax  : (65) 2728418 
Singapore 118230 		   Email: [email-masked] 
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