In 2012 New York was battered by a whomping great hurricane called Sandy. The Brooklyn neighbourhood of Red Hook was hit particularly badly, with telephone and net services knocked out.
The situation was potentially disastrous. With communications down, emergency service responders had at first little idea how to prioritise deployment; the injured, the sick and scared had no clue when help would arrive.
Red Hook's sudden isolation was a graphic example of how modern telecommunications infrastructure is inherently fragile - and how utterly dependent on it we have become.
Thus, the killer question: what happens when the internet fails? For the New Yorkers, the answer lay in the presence of another communications network - a rough and ready, quick and dirty, do-it-yourself mongrel set-up known generically as a "meshnet".
Meshnets are essentially local area networks cobbled together from router-connected wireless devices such as smartphones and tablets, powered by batteries or generators. The devices constitute "nodes" in the system, and transmit information between themselves over short distances.
Some enabling software and a lot of tech savvy are required to establish a meshnet. The system is inherently wonky, limited by battery power and location.
From another perspective, however, it is remarkably strong. Data zips between nodes autonomously, bypassing broken bits, and is thus "self-healing" in the jargon. It is also - and this is an aspect attractive to many - independent of big outfits such as Google.
The people of Red Hook were fortunate that a mob of locals had already been busy building a meshnet. The system was sufficiently mature that the Federal Emergency Management Agency was able to hook it up to its satellite system, linking itself, the residents and the Red Cross into an effective communication matrix.
There are quite a few bits of software that can underpin meshnet formation. Some need to be hacked, and most present significant challenges if they have to be downloaded post-disaster when online stores are inaccessible. The newest and perhaps most promising meshnet-enabler on the market is a program called Commotion. Still in beta form, it is available free for developers and end-users alike and is the product of a US non-profit group called the Open Technology Institute (OTI).
Commotion catalyses the development of peer-to-peer networks running off wireless devices. Somewhere in the mix there has to be an internet connection, jacked into a Commotion-enabled router. The router then shares the bandwidth with all other nodes in the mesh, allowing communication without the need for data to pass through a central hub.
Field trials of Commotion are under way in many communities, from Google-shy hactivists in Manhattan, to towns in countries such as Tunisia, where standard internet is sometimes blocked by government.
"Because mesh networks are self-healing and able to route around points of failure, one of the primary-use cases we envision for mesh technology is resilience and disaster response," says Greta Byrum, OTI's acting field operations director.
"But disasters can take many different forms, from sudden catastrophic weather events to the kind of slow economic collapse that overtook Detroit at the end of the last century," she says.
"Mesh is a technology that can give communities control over their own communications infrastructure, which is useful whether you're addressing entrenched poverty - one of the most common reasons that people don't subscribe to broadband services - or responding to a catastrophic weather event."
Byrum stresses that mesh networks are not easy solutions to either catastrophe or repression. It is definitely not an out-of-the-box, plug-and-play option. Establishing a mesh requires planning, know-how, and community co-operation. Maintaining a mesh requires frequent tweaking and tinkering.
To work effectively, need and foresight must first combine. To this end, OTI is currently working with residents in the town of Sayada, Tunisia, assisting them to create an autonomous meshnet that will continue to operate during government-led telecommunications crackdowns.
The SayadaNet, as it's called, currently runs local versions of Open Street Maps, Wikipedia, a library and a chat server.
OTI is well aware that independent communications networks aren't popular with many governments, including that of the US. Greta Byrum makes no apologies.
"Digital connectivity has become absolutely central to participation in government, culture and the economy," she says. "We must challenge any interests that limit or restrict our ability to design communications tools that truly meet our needs.
"That said, the logic of creating distributed, open tools like Commotion is that they can be adopted widely by dispersed groups of stakeholders around the world, so there's no single point of control to be targeted by opposition. Like a mesh network, the distributed community of users itself reflects a unique kind of resilience."
- The Age