[Cu-wireless] mesh-net ready AP's?

David Young dyoung at pobox.com
Fri Feb 6 23:32:00 CST 2004

On Fri, Feb 06, 2004 at 04:55:27PM -0800, spamtanic at yahoo.com wrote:
> Just heard Paul R. mention (on WEFT MediaGeek live) a
> big grant that cu-wireless has received to implement a
> mesh net.  

Yep. The grant pays for one year of open-source software development
and the construction and installation of 32 nodes in Urbana. It also
pays for us to create 2-3 kits of 9 or 6 nodes, each, for distribution
in the rest of the world.

The software consists of a "mesh" routing daemon, an innovative "ad
hoc" name service, a user interface, software for high-reliability,
and on-line software upgrades.

Our routing daemon will be a major innovation in the open-source "mesh"
world. It will be the first open-source implementation of Hazy Sighted
Link State (HSLS) routing. HSLS enables exceptional scalability in the
wireless environment, and yet it has an uncomplicated implementation.
We are going to couple HSLS with a proven wireless routing metric,
called ETX. ETX helps HSLS choose the high-performance paths in the
network by assigning them costs based on the rate they drop packets.
Assigning costs to wireless links is abosolutely essential for
good performance.  Another important innovation is that the HSLS
daemon is going to interoperate with Quagga (formerly Zebra), which
both provides our kernel abstraction and also lets us interface with
existing RIP/OSPF/BGP networks.  The Quagga interface is an important
stepping-stone to producing a multi-homed network.  You can find papers
and technical reports about HSLS on the Web (authors: Ram Ramanathan
and Cesar Santivanez). ETX and Quagga are documented on-line, too.

> What brands/models of AP's are "mesh-net ready", or
> will those/any newly deployed be "roll yer own" style?

Barring a major breakthrough in 802.11 AP hacking, the 32 new nodes in our
outdoor testbed will resemble the existing nodes: Soekris single-board
computers with 802.11b radios, outdoor enclosures, 64MB CompactFlash,
and 8dBi antennas.

[I am personally very interested in the low-cost (80AUD ~ 50USD) 802.11b
 APs by Minitar, which contain the Realtek RTL8181 "system on a chip"
 (SoC). APs based on Atheros' SoC also appeal. Incidentally, I am
 programming an open-source, NetBSD driver for the RTL8181's wireless
 bits, and somebody else is porting NetBSD. The RTL8181 docs have
 "leaked." Also, there is a glimmer of hope that we can get hold of docs
 for the Atheros chip.]

> I remember skimming a detailed tech doc that
> cuwireless hosted over a year ago, describing a
> bare-bones 'nix-on-flashRAM board, mounted in an ammo
> can.  Still gonna use those?

We have been very pleased with our ammo can routers, but we have decided
that the hours spent prepping a can are better spent programming. We buy
our enclosures, now. Otherwise our setup is very similar. I would like
to someday put on the web some photos of the ammo can for the curious.

> I also see Sascha and Dave have started a sourceforge
> repository for software development, so this is going
> to be primarily an open-source software scheme, using
> "dumb" hardware (?)

Yes, everything will be open-source under a BSD-style license.

> Just generally curious, but coming up empty-handed
> while looking for more info.  'S'all positive and
> exciting news, nevertheless!  Saw mention of VOIP as
> an option too.  Right on.

Yes, we want to roll out VoIP. Actually, there is a household on our
network that is without a phone; they might be interested in VoIP. Contact
Sascha or I if you would like to experiment with VoIP on our network. We
will find a way to support you and to integrate your work with ours.
Research would be enormously useful. I have questions about SIP, H.323,
OpenH323, VoIP codecs, VoIP PC cards & phones, VoIP->PSTN gateways:
what software support do they need for us to install on the wireless
nodes? how expensive are they? how can a grassroots network adapt each
to an "ad hoc" environment?


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

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