more than spread spectrum

There are alternatives to spread spectrum, if we're threatened with
loss of freedom to communicate.

We could lay our own wires/fibers.

We could set up a mesh network of infrared lasers through the air.  Last
time I looked, there were no laws against shining lights out your window as
long as they didn't bother anyone.  An infrared laser could hardly bother
anyone.

We could produce a line of cheap cards to plug into a PC which would do
packet routing, using a variety of physical links -- our own wires, lasers,
very low range radio, ....  Each card would connect to three or more
neighbors and become part of the global mesh.  Adaptive routing with no
global map would suffice for the card and would keep the whole system
peer-to-peer with no need for central control and no chance for central
tapping.

Of course all of these solutions require a high density of users.  A
college campus might be the right place to start.  We could then branch out
to cities.  I suspect that a place like Chicago or NYC with high rise
apartments might be the place to start -- many options for line-of-sight
communications.


The benefit isn't just for Cypherpunks.  It's a free network for the masses
-- like the original USENET (with each user donating routing and
store/forward) but with unrestricted, low-range, continuously operating
physical links.


I'll volunteer to do the software for the node card.  Does anyone have
hardware design/fab to donate to the effort?

 - Carl

This idea of setting up your own independent network isn't as far fetched
as it sounds, at least in a relatively local area with critical mass.

The router nodes already exist, in the form of my own TCP/IP code for
the PC, or any of several other packages including the various freeware
UNIX clones.

Radio transmission equipment operating under Part 15 of the FCC rules
is already available. Under Part 15, you don't need a license; the
radio transmitter does have to be "type accepted" by the FCC but since
you buy that as a prepackaged box you don't have to worry about it.

The section of Part 15 that is particularly interesting is either
15.247 or 15.249 (can't remember which).  It allows you to run up to 1
watt of power, quite a bit for an unlicensed service, on any of
several "ISM" (aka "garbage") bands as long as you use spread spectrum
with a minimum processing gain of 10dB. The most popular is 902-928
Mhz, with another band in the vicinity of 2450 Ghz coming up fast.
Ahthough most Part 15 equipment is designed primarily for use within
office environments, it can be and is used over point-to-point paths
of 5-10 km with the proper directional antennas.

Although Part 15 users are not allowed to cause harmful interference
and must accept interference from other users (microwave ovens
generally operate on 2450 Mhz), in practice these nets seem to work
pretty well if they're properly engineered. Besides, the inherent
distributed redundancy available in a packet network should be able to
compensate for momentary outages due to interference.

Unlike the amateur service, which has some particularly draconian
"acceptable use" policies (despite a recent liberalization, encryption
is still illegal), there are *no* restrictions on the use of Part 15
equipment. Encryption is not only legal, some boards have hardware
encryption support (e.g., the NCR Wavelan has a DES chip). This
particular board operates at 2 megabits/sec on the 902-928 Mhz band
with 250 mW of power.

There is an even more interesting development in the works: "data
PCS".  In essence, this is "Part 15" style operation on dedicated
spectrum, i.e., new spectrum in the 1.8-2.2 Ghz band that will not
have to be shared.  The specific intent of data PCS is to allow users
to build their own ad-hoc networks without having to rely on the facilities
of (and pay money to) carriers such as telephone companies.

Phil

In <9309150353.AA06198@ellisun.sw.stratus.com>, Carl Ellison wrote...
> There are alternatives to spread spectrum, if we're threatened with
> loss of freedom to communicate.
> 
> We could lay our own wires/fibers.
> 

Well, we'd like crypto for the masses and I don't think that the masses are
yet ready to put out the bucks for spread spectrum boards and infrared laser
communications gear...  It'd be really nice to have such a decentralized
network, though.

> We could set up a mesh network of infrared lasers through the air.  Last
> time I looked, there were no laws against shining lights out your window as
> long as they didn't bother anyone.  An infrared laser could hardly bother
> anyone.
> 
...
> very low range radio, ....  Each card would connect to three or more
> neighbors and become part of the global mesh.  Adaptive routing with no
> global map would suffice for the card and would keep the whole system
> peer-to-peer with no need for central control and no chance for central
> tapping.
> 

This would be the perfect network in which to deploy DC nets....  (dining
cryptographers).



;; __________________________________________________________________________
;; Stig@netcom.com                            netcom.com:/pub/stig/00-PGP-KEY
;; It's hard to be cutting-edge at your own pace...   32 DF B9 19 AE 28 D1 7A
;; Bullet-proof code cannot stand up to teflon bugs.  A3 9D 0B 1A 33 13 4D 7F

In reply to (Carl Ellison):

| I'll volunteer to do the software for the node card.  Does anyone have
| hardware design/fab to donate to the effort?

Hmm, this is nice timing I guess :-)

Over the last 3-4 weeks I have been mulling over in my head (you know,
that process before you actually start putting down on paper) a design
for a relatively 'simple' learning bridge, using off the shelf support
chips. I'm currently in the middle of an academic semester, and if I
don't happen to work during the coming break (for the non-australians,
our academic year is mar->nov), then this is something I will take up.

The actual design I have in mind has a 839X IEEE802.3 CSMA/CD ethernet
controller on the network side plus an 8088 embedded controller to do
all the work (or, maybe something else, but 8088 assembly is familiar 
to me and its a real cheap chip). The output stage is a synchronous 
HDLC varient (SABM mode, cut down for pp operation) running at a select-
able synch rate (anywhere from 19.2k to 10mbps, obviously @ 19.2k you 
would have problems on a loaded ethernet).

One of the main reasons for starting this is that another colleague of
mine has an interest in constructing the 2mbps microwave (10GHz) project
as seen in your local ARRL handbook. This would tie in nicely, but
further to this, it has the possibility to interface to any communications
medium you desire (as long as it can handle a synch incoming data stream).
It oculd plug into the other side of a spread-spectrum board, it could
be used with an async interface and a pc to tunnel traffic across
another network, and so on.

There is also a possibility to use some of the HDLC initialisation
phases to exchange public keys :-), and to encrypt information frames
(headers == plaintext) on the fly. 'Generic' and 'Modular' is a basic
philosophy of mine. If I do have the time, and complete this project,
then I hope to make it 'available' to the masses (so to speak). I can
envisage that there would be people interested in such a setup.

As an undergrad Computer Systems Engineer student, there are no problems
with access to appropriate design and testing equipment, its just a 
matter of me getting the time.

Of course, all this is 'in my head' at the moment, so nothing is definite.
Discussion, ideas and pointers are welcome, although the technical side
of things maybe straying from the cypherpunk agenda.

Matthew.
-- 
Matthew Gream,, M.Gream@uts.edu.au -- Consent Technologies, 02-821-2043.