Can a million New York city devices be programmed for true peer-to-peer? [closed]

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If Chris and Pat want to exchange a text message, they send and receive via their network providers, which charge them for a connection.

If Chris and Pat are both located in New York City, and there are enough wireless devices between Chris and Pat all close enough to each other to form a continuous chain, is it possible for all those devices to be programmed to cooperatively forward packets amongst each other, bypassing the need for network providers?

It would seem the "address" of each device would have to include current geographic coordinates, and devices would have to report their movements frequently enough so routing attempts could still find them, but the speed and capacity of devices nowadays could handle that, right?

Would such a network be viable? Does it already exist or has it been attempted? Is there some kind of inherent programming problem that is difficult to overcome?

Answer 1

If everyone has a device with sufficient receive/process/send capabilities, then backbones (ISP's) aren't really necessary. Start at mesh networking to find the huge web of implementations, devices, projects, etc., that have already been in development. The early arpanet was essentially true peer-to-peer, but the number of net nodes grew faster than the nodes' individual capabilities, hence the growth of backbones and those damn fees everyone's paying to phone and cable companies.

Eventually someone will realize there are a million teenagers in NYC that would be happy to text and email each other for free. They'll create a 99-cent download to let everyone turn their phones and laptops and discarded devices into routers and repeaters, and it'll go viral.

Someday household rooftop repeaters might become as common as TV antennas used to be.

Answer 2

There are a few interesting things here:

1. Reachability. At least you need to use a technology that can do ad-hoc and peer-to-peer networking. Of those technologies only bluetooth, NFC and WiFi are more or less often implemented. Of those again only wifi currently may have the strength to connect to devices in other houses or to the street, but even there typical ranges are 30-60m (and that's for APs, it might be lower for UEs).
2. Mobility. ANY short-range wireless communication protocol has difficulties with fast-moving devices. It's simple math, suppose your coverage is 50m in diameter, if you move at about 20km/h or 5.5m/s, you have less than 10s to actually detect, connect and send data while passing this link. Oh, but then we did not consider receiving traffic, you actually have to let all devices know that for the next 10s you want to receive data now via this access network. To give an example, wifi connectivity times with decent authentication (which you need for something like this) alone takes a few seconds. 10s might be doable, but as soon we talk about cars, trains, ... it's becoming almost impossible with current technology. But then again, if you can't connect to those, what are the odds you will cross some huge boulevards with your limited reachability?
3. Hop to hop delays. You need a lot of those. We can fairly assume that you need at least a hop each 20-30m, let's average at 40 hops/km. So to send a packet over lets say 5km you'd need 200 hops. Each hop needs to take in a packet (L2 processing), route it (L3 processing) and send it out again (L2 processing). While mobile devices are relatively powerful these days I wouldn't assume they can handle that in the microseconds routers do. Next to that in a wireless network you have to wait for a transmission slot, which can actually take in the order of ms (each hop!). So all in all, odds are huge this would be a terribly slow network.
4. Loss. Well, this depends a bit on the wireless protocol, either it has its own reliable delivery protocol (which will make the previous point worse) or it doesn't. In that last case, suppose your wireless link has about .1% loss, or 99.9% no-loss, this would actually end up with an 18.1% loss rate for the 200 hops considered previously ( (1-0.999**200)*100) This is nearly impossible to work with in day-to-day communications.
5. Routing. lets say you need a few millions of devices and thus routes. For traditional routing this usually takes some very heavy multicore routers with loads of processing power. Let's just say mobile devices (today) can't cut that yet. A purely geographically based routing mechanism might work, but I can't personally think of any (even theoretical) system for this that works today. You still have to distribute those routes, deal with (VERY) frequent route updates, avoid routing loops, and so on. So even with that I'd guess you'd hit the same scale issues as with for example OSPF. But all-in-all I think this is something that mobile devices will be able to handle somewhere in the not-so-far future, we're just talking about computing capacity here.

There are some other points why such a network is very hard today, but these are the major ones I know of. Is it impossible? No, of course not, but I just wanted to show why I think it is almost impossible with the current technologies and would require some very significant improvements, not just building the network.

Answer 3

Please check: Wireless sensor network

A wireless sensor network (WSN) of spatially distributed autonomous sensors to monitor physical or environmental conditions, such as temperature, sound, pressure, etc. and to cooperatively pass their data through the network to a main location