Subject: RE: [manet] Re: MANET definition of a neighbor

From: "Mullen, John" <[email-masked]>
Date: Fri, 5 May 2006 09:00:59 -0600

Hi Dan,

It doesn't work that way.  The chances of selecting a bad link may,
depending on the scheme you pick, be higher than that of picking a good
on.  In field trials, this has turned out to be a major source of
trouble.  Repeated attempts will simply lead to repeated bad choices. 

John P. Mullen, Ph.D.
(505) 646-2958
[email-masked]
 
-----Original Message-----
From: DANIEL BYRNE [mailto:[email-masked]] 
Sent: Thursday, May 04, 2006 3:01 PM
To: Mullen, John; [email-masked]
Subject: RE: [manet] Re: MANET definition of a neighbor

Hi Dan,

The problem is that the node doesn't know which links are good and must
make intelligent guesses.  If you rebuild your table without reason to
suspect a route is bad, you will increase the risk of excluding a good
route or including a bad one.

- If you accidently include a bad route, it will be weeded out in the
next cycle or two.  The trick is to update fast enough so that the bad
routes don't have a lasting impact.

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---

From: David Young <[email-masked]>
Date: Sun, 7 May 2006 23:21:33 -0500

> trouble.  Repeated attempts will simply lead to repeated bad choices. 

Three observations, and a question: (1) Any choice of a single receiver
may be a bad choice, most of the time.  (2) The link conditions may not
outlast the decision process.  (3) You will broadcast the packet at the
physical layer, anyway---i.e., more than one receiver will receive it.
So, why choose?  (It only occurs to me to ask because I have fallen
under the influence of the Roofnet ExOR[1] study.)

Dave

[1] http://pdos.csail.mit.edu/papers/roofnet:exor-sigcomm05/roofnet_exor-sigcomm05.pdf

-- 
David Young             OJC Technologies
[email-masked]      Urbana, IL * (217) 278-3933