Subject: Re: Flooding & Hidden Terminal?

From: "Dave Springall" <[email-masked]>
Date: Mon, 14 Sep 1998 20:13:38 +0100

Chip,

This is a problem that I identified some while ago which I mentioned a year
or so ago (actually at the UMD Conference in March 97), but I don't think
the people I mentioned it to were all that concerned at the time.   I have
now
assumed that the problem has been sucessfully dealt with.

I've been working other things since then, but my simulations (that simulate
the physical and MAC layers) have indicated quite a performance problem with
a broadcast packet.   The vital question is, whether this performance hit is
permissable given the behavior of the routing protocol.  Ie.  is the routing
protocol going to be flooding the network often, or just during the period
before its reaches its stable state.

I simulated a modified version of MACAW that supports a guaranteed broadcast
method, that isn't affected by hidden terminals and under normal conditions
can be quite efficient.   This work also lead me to consider the possibility
of
placing some of the tasks carried out by the routing layer into the MAC
layer for efficiency purposes.  Ie. piggybacking small amounts routing
information on MAC level control packets.

Again, I have been distracted by other projects since then, but if there is
enough interest I can dig out the remnants of my simulator (C++) and provide
a more lucid description of my work.

Many thanks
Dave Springall
Department of Computer Science
Royal Holloway, University of London