In my first post on the community mesh network, I mentioned that we are at disadvantage politically and at relatively a better place technologically.
Well I was wrong. Though we have gathered some knowledge over mesh network over the period, we are still years behind in installing a city or even a street scale mesh network.
The harware was the problem. We are not in a position to afford a dual band router(which operated over both the bands 2.4Ghz and 5Ghz, simultaneously/concurrently) because the single band routers degrades the bandwidth geometrically with the diameter of the network. The price of a openwrt compatible concurrent dual band router available in India starts around Rs.11000, which is too expensive for just a router.
So we had to look at alternatives options. How to build a concurrent dual band Wifi device(we haven't looked other physical layer protocols as of now, I think we should). The following are the alternatives that we have come up with.
- Wifi-dongle with RaspberryPi[2]
- Project Turris
- Gl-inet devices
- A normal PC with PCI(e) Wifi adapter
- Software Defined Radio
Wifi-dongle with RPi (Rs.5000)
Our survey over the internet forums have suggested that the RPi will not be able to handle the needs of a router. We had planned to test this claim. We have not pursued it, because we do not have access to dual band Wifi dongle yet(Yes, we are broke)Project Turris (Not available for sale in India)
This is a project to develop open source router, an NAS server. They have designed their own hardware and distribute it with a custom operating system called, surprise surprise - Turris OS. It is not available for sale in India.Gl-inet AR300MD (Not yet in production)
They manufacture openwrt compatible networking devices. We are interested in their AR300MD variants which are not available yet. Yes, D stands for dual band. We have asked them about it launch, but there is no definitive idea on that yet.Wifi-adapter/PC (Rs.11000)
The cheaper dual core intel or amd desktops paired with a dual band wifi adapter makes viable candidate for meshnet. The desktops costs 5k and the wifi-dapter costs 6.5k, so approximately the total costs is around 10k to 12k. I think it makes sense to spend 11k on a full desktop instead of just a router box. Of course it will consume more power than a router. If we can make use of power optimizations (like dynamic clocking) in linux, this is a good bet.SDR (no clear idea)
What is SDR? go to Wikipedia. It is ultimately the best platform for community meshnet given its versatile capabilities. It comes in two varieties, where radio components that have been typically implemented in hardware are instead implemented by means of software on a personal computer or embedded system.We just had a meetup today where many of its merits surfaced. Imagine a device every 10meters capable of monitoring itself and its environment, which can adapts itself to the situations so the communication is never brought down due to technical and political nuances. Would it be possible to transport IP packets over FM radio? It might be. I don't know yet.
Which one to choose?
Forgive me for this boring essay so far. "Why are you stating these obvious things?" you may ask. The actual post starts here. That is just the prelude. Please bear with me for few more words. I can assure you that it will be worth your time(if you're into mesh-net)Our idea is to kickstart this mesh-community with PC based mesh nodes. A desktop with wifi-card can serve as a beasty router. Well not just a router. It can do much more than that. We can host content in the desktop - every node in the mesh is a web-server now. It can act as an SDR, practically providing us with some(Wifi-card is not a programmable component) of the benefits of SDR(what if could design a SDR card that could be plugged into a desktop?)
At this point, "come on man, who will buy a full desktop instead of a cheap router, especially when they already have a computer at home." you will say.
Well you're right. That is why I think we should impart his idea into school students. Also we can talk to computer sales centers, to see if we can cut a deal in order to proliferate this device. But again its merits weigh high in my balance.
Up until this point the merits I have been talking in the sense of single device. The desktop could run a lot more sophisticated protocols and algorithms to accomplish much more than what a router can do. The mesh nodes can balance loads and schedule operations intelligently. A node operator can inform the network that how long this particular node will be up, and the nework shall adapt itself according to such instructions(or clues?).
As for the content distribution, a torrent like protocol can used to share commons' content. Anyone could author articles. Journalism - decentralized. A social network which we envision(a new post coming up) designed run over such mesh network will make an awesome tool for journalism.
Couple of caveats - power consumption, and bulky. That is it on the hardware side.
We also started to work on documentation and training sessions for beginners. Ganesh and Mugil are kind enough to offer us a session on introduction on communicaion engineering, and Roopak and his friends from Trichy are coming to Pondicherry for the same. Awaiting the day.
As most of my essays, this one also might be random ramblings, please let me know your thoughts
[1] So far we haven't looked into linux distros other than OpenWRT
[2] Or any other embedded platform which can run linux
