Re: TECH: wireless gets real

From: Ken Clements (
Date: Mon Jul 09 2001 - 13:03:08 MDT

Eugene Leitl wrote:

> For years I keep harping about how currently used routing techniques are
> so very b0rken. Cellular wireless by its very nature is ideal for geodetic
> routing, which uses local-visibility routing tables strictly. Meaning, all
> the admin traffic is purely local, among immediate, and
> neighbours'-neighbour nodes. Meaning, the thing is infinitely scalable, as
> bits are sufficiently cheap to be able to address the entire visible
> universe at Planck scale, if you think you need to do that. Mapping the
> entire solar system down to cubic micron is a piece of cake.
> As a boon, if you use geographic coordinates for node addresses (obtained
> from connectivity constraints or plain old GPS), you can't get address
> collisions (no two nodes can occupy the same place at the same time), and
> you can use switching instead of routing, if you design the packet header
> layout right.

Dear Eugene,

Be very careful about using geographic data for wireless routing. Plenty of
folks have done this in the past and been sorry. You can get pointers by
asking Google for "wireless geographic routing." Also have a look at my post:

Geographic routing works well in places where the physical space maps well
into the communication link space (Kansas) and is problematic when it does not
(Manhattan). The shortest physical distance may not be the shortest latency.
Wireless links are stochastic. Just because you got a packet through a link
quickly this time, does not mean you will be able to do so next time. Often
the best route in communication space looks very strange when you see it
represented on a map.


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