[CWN-Summit] Re: OPeN & community wireless networking

[David Young]

On Sat, Nov 27, 2004 at 12:02:14PM -0600, cwn-summit-request at lists.cuwireless.net wrote:
> Message: 1
> Date: Sat, 27 Nov 2004 02:43:55 -0600 (CST)
> From: Sascha Meinrath <sascha at ucimc.org>
> Subject: [CWN-Summit] OPeN & community wireless networking: 
> To: cwn-summit at cuwireless.net
> Message-ID: <Pine.LNX.4.61.0411270230280.7376 at imsahp.cu.groogroo.com>
> Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed
> 
> Hi everyone,
> 
> Matt Westervelt brought a crazy idea to team CUWiN while were were all in 
> Denmark together a couple months back -- that community wireless networks 

I find this phrasing a little peculiar, so interpreting: Matt came to
FreiFunk talking about OPN.  Everybody who he told about it thought it
was cool.  He incited several impromptu discussions about it; some of
us from CUWiN were privileged to attend.  Later, Matt and James Stevens
presented the idea.  It inspired a lot of us at Freifunk: OPN solves
problems in "bootstrapping" new community wireless networks, and it leads
one to conceive of the neighbor's AP as a network resource rather than
a nuisance.

> It would be extremely useful if folks would take a few minutes to look it 
> over and comment on any potential flaws (or brilliant solutions) to the 
> idea.  We need both technical and non-technical eyes on the proposal.

Is that the royal we? :-)

There is no question that OPN can be implemented in open source using
several of the common 802.11 client adapters.  The adapters with 802.11
ASICs from Atheros, Ralink, ADMtek, and Realtek are appropriate.

As Matt and James' explanation mentions, <http://dek.spc.org/opn/>,
Microsoft Research demonstrated Atheros radios operating simultaneously
on more than one network, even networks of disparate types (ad hoc &
infrastructure) and on different channels (6 & 11).  They called the
result MultiNet.  The way it works is that the radio switches rapidly
between the networks/channels without dropping its state of AP/client
association.  Also, a MultiNet client cleverly exploits the 802.11
power-saving facility to make an access point buffer the client's packets
while it visits another channel.  In this way, no packets need be dropped
just because the receiver is off-channel.

Microsoft's work is reproducible in open source.  You have to modify
the device driver to do it.  Programming device drivers is something I
do for fun and for profit; I'm looking forward to implementing OPN in
my hobby time at my earliest opportunity---looks like late winter or
early spring.  I have a software architecture in mind for OPN which I
will write up considerably sooner.

Dave

-- 
David Young             OJC Technologies
dyoung at ojctech.com      Urbana, IL * (217) 278-3933