BGP (in)security makes the AP wire

Neil Harris neil at tonal.clara.co.uk
Fri Feb 18 07:42:14 CST 2011


On 18/02/11 12:26, Eugen Leitl wrote:
> On Sun, May 09, 2010 at 09:38:18AM -0700, Joel Jaeggli wrote:
>
>> geographic location doesn't map to topology
> In LEO satellite constellations and mesh wireless it typically does.
> When bootstrapping a global mesh, one could use VPN tunnels over
> Internet to emulate long-distance links initially.
>
> Eben Moglen recently proposed a FreedomBox intitiative, using ARM
> wall warts to build an open source cloud with an anonymizing layer.
> Many of these come with 802.11x radio built-in. If this project
> ever happens, it could become a basis for end-user owned
> infrastructure. Long-range WiFi can compete with LR fiber
> in principle, though at a tiny fraction of throughput.
>

"Tiny fraction" is putting it mildly. I once considered starting up a 
low-infrastructure wireless ISP using mesh radio based on wifi radio 
technology adapted to work in licensed bands.

If you work out the numbers, the bandwidth you get in any substantial 
deployment is pitiful compared to technologies like DSL and cable 
modems, let alone fiber.

New technologies such as distributed space-time multipath coding on the 
wireless side, and multipath network coding on the bitstream side, look 
like the way forward on this, but these are brand new, and still the 
subject of research -- you certainly can't just hot-wire these onto wifi 
hardware.

>>> Presumably, one could prototype something simple and cheap at L2 level
>>> with WGS 84->MAC (about ~m^2 resolution), custom switch firmware and GBIC
>>> for longish (1-70 km) distances, but without a mesh it won't work.
> The local 64 bit part of IPv6 has enough space for global ~2 m resolution,
> including altitide (24, 24, 16 bit). With DAD and fuzzing lowest
> significant bits address collisions could be prevented reliably.
>
> Central authority and decentralism can co-exist.

Indeed.

The fact that the usable bandwidth resulting from ad-hoc mesh wiki would 
be tiny compared to broadband connections doesn't mean this sort of 
thing isn't worth trying: a few tens of kilobits a second is plenty for 
speech, and even a few hundred bits per second useful for basic text 
messaging.

Given that the cost of doing this is almost zero, since only software is 
required to implement it on any modern wifi/GPS equipped mobile 
hardware, this seems like a great thing to have in the general portfolio 
of networking technologies: having something like this available could 
be invaluable in disaster/crisis situations.

-- Neil





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