You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
716 lines
36 KiB
716 lines
36 KiB
4 years ago
|
### How to Build a Low-tech Internet
|
||
|
|
||
|
Wireless internet access is on the rise in both modern consumer
|
||
|
societies and in the developing world.
|
||
|
|
||
|
In rich countries, however, the focus is on always-on connectivity and
|
||
|
ever higher access speeds. In poor countries, on the other hand,
|
||
|
connectivity is achieved through much more low-tech, often asynchronous
|
||
|
networks.
|
||
|
|
||
|
While the high-tech approach pushes the costs and energy use of the
|
||
|
internet [higher and
|
||
|
higher](https://www.lowtechmagazine.com/2015/10/can-the-internet-run-on-renewable-energy.html),
|
||
|
the low-tech alternatives result in much cheaper and very energy
|
||
|
efficient networks that combine well with renewable power production and
|
||
|
are resistant to disruptions.
|
||
|
|
||
|
If we want the internet to keep working in circumstances where access to
|
||
|
energy is more limited, we can learn important lessons from alternative
|
||
|
network technologies. Best of all, there\'s no need to wait for
|
||
|
governments or companies to facilitate: we can build our own resilient
|
||
|
communication infrastructure if we cooperate with one another. This is
|
||
|
demonstrated by several community networks in Europe, of which the
|
||
|
largest has more than 35,000 users already.
|
||
|
|
||
|
[]{#anchor}Picture: A node in the [Scottish Tegola
|
||
|
Network](http://www.tegola.org.uk/hebnet/).
|
||
|
|
||
|
More than half of the global population does not have access to the
|
||
|
\"worldwide\" web. Up to now, the internet is mainly an urban
|
||
|
phenomenon, especially in \"developing\" countries. Telecommunication
|
||
|
companies are usually reluctant to extend their network outside cities
|
||
|
due to a combination of high infrastructure costs, low population
|
||
|
density, limited ability to pay for services, and an unreliable or
|
||
|
non-existent electricity infrastructure. Even in remote regions of
|
||
|
\"developed\" countries, internet connectivity isn\'t always available.
|
||
|
|
||
|
Internet companies such as Facebook and Google regularly make headlines
|
||
|
with plans for connecting these remote regions to the internet. Facebook
|
||
|
tries to achieve this with drones, while Google counts on high-altitude
|
||
|
balloons. There are major technological challenges, but the main
|
||
|
objection to these plans is their commercial character. Obviously,
|
||
|
Google and Facebook want to connect more people to the internet because
|
||
|
that would increase their revenues. Facebook especially receives lots of
|
||
|
criticism because their network promotes their own site in particular,
|
||
|
and blocks most other internet applications. \[1\]
|
||
|
|
||
|
Meanwhile, several research groups and network enthusiasts have
|
||
|
developed and implemented much cheaper alternative network technologies
|
||
|
to solve these issues. Although these low-tech networks have proven
|
||
|
their worth, they have received much less attention. Contrary to the
|
||
|
projects of internet companies, they are set up by small organisations
|
||
|
or by the users themselves. This guarantees an open network that
|
||
|
benefits the users instead of a handful of corporations. At the same
|
||
|
time, these low-tech networks are very energy efficient.
|
||
|
|
||
|
****WiFi-based Long Distance Networks****
|
||
|
|
||
|
Most low-tech networks are based on WiFi, the same technology that
|
||
|
allows mobile access to the internet in most western households. As we
|
||
|
have seen in the previous article, [sharing these devices could provide
|
||
|
free mobile access across densely populated
|
||
|
cities](https://www.lowtechmagazine.com/2015/10/the-4g-network-thats-already-there.html).
|
||
|
But the technology can be equally useful in sparsely populated areas.
|
||
|
Although the WiFi-standard was developed for short-distance data
|
||
|
communication (with a typical range of about 30 metres), its reach can
|
||
|
be extended through modifications of the Media Access Control (MAC)
|
||
|
layer in the networking protocol, and through the use of range extender
|
||
|
amplifiers and directional antennas. \[2\]
|
||
|
|
||
|
Although the WiFi-standard was developed for short-distance data
|
||
|
communication, its reach can be extended to cover distances of more than
|
||
|
100 kilometres.
|
||
|
|
||
|
The longest unamplified WiFi link is a 384 km wireless point-to-point
|
||
|
connection between Pico El Águila and Platillón in Venezuela,
|
||
|
established a few years ago. \[3,4\] However, WiFi-based long distance
|
||
|
networks usually consist of a combination of shorter point-to-point
|
||
|
links, each between a few kilometres and one hundred kilometers long at
|
||
|
most. These are combined to create larger, multihop networks.
|
||
|
Point-to-points links, which form the backbone of a long range WiFi
|
||
|
network, are combined with omnidirectional antennas that distribute the
|
||
|
signal to individual households (or public institutions) of a community.
|
||
|
|
||
|
Picture: A relay with three point-to-point links and three sectoral
|
||
|
antennae.
|
||
|
[Tegola](http://www.tegola.org.uk/howto/network-planning.html).
|
||
|
|
||
|
Long-distance WiFi links require line of sight to make a connection \--
|
||
|
in this sense, the technology resembles the [18th century optical
|
||
|
telegraph](https://www.lowtechmagazine.com/2007/12/email-in-the-18.html).
|
||
|
\[5\] If there\'s no line of sight between two points, a third relay is
|
||
|
required that can see both points, and the signal is sent to the
|
||
|
intermediate relay first. Depending on the terrain and particular
|
||
|
obstacles, more hubs may be necessary. \[6\]
|
||
|
|
||
|
Point-to-point links typically consist of two directional antennas, one
|
||
|
focused on the next node and the other on the previous node in the
|
||
|
network. Nodes can have multiple antennas with one antenna per fixed
|
||
|
point-to-point link to each neighbour. \[7\] This allows mesh routing
|
||
|
protocols that can dynamically select which links to choose for routing
|
||
|
among the available ones. \[8\]
|
||
|
|
||
|
Long-distance WiFi links require line of sight to make a connection \--
|
||
|
in this sense, the technology resembles the 18th century optical
|
||
|
telegraph.
|
||
|
|
||
|
Distribution nodes usually consist of a sectoral antenna (a small
|
||
|
version of the things you see on mobile phone masts) or a conventional
|
||
|
WiFi-router, together with a number of receivers in the community. \[6\]
|
||
|
For short distance WiFi-communication, there is no requirement for line
|
||
|
of sight between the transmitter and the receiver. \[9\]
|
||
|
|
||
|
To provide users with access to the worldwide internet, a long range
|
||
|
WiFi network should be connected to the main backbone of the internet
|
||
|
using at least one \"backhaul\" or \"gateway node\". This can be a
|
||
|
dial-up or broadband connection (DSL, fibre or satellite). If such a
|
||
|
link is not established, users would still be able to communicate with
|
||
|
each other and view websites set up on local servers, but they would not
|
||
|
be able to access the internet. \[10\]
|
||
|
|
||
|
****Advantages of Long Range WiFi****
|
||
|
|
||
|
Long range WiFi offers high bandwidth (up to 54 Mbps) combined with very
|
||
|
low capital costs. Because the WiFi standard enjoys widespread
|
||
|
acceptance and has huge production volumes, off-the-shelf antennas and
|
||
|
wireless cards can be bought for very little money. \[11\]
|
||
|
Alternatively, components can be put together [from discarded
|
||
|
materials](http://roelof.info/projects/%282014%29Pretty_Fly_For_A_Wifi/)
|
||
|
such as old routers, satellite dish antennas and laptops. Protocols like
|
||
|
WiLDNet run on a 266 Mhz processor with only 128 MB memory, so an old
|
||
|
computer will do the trick. \[7\]
|
||
|
|
||
|
The WiFi-nodes are lightweight and don\'t need expensive towers \--
|
||
|
further decreasing capital costs, and minimizing the impact of the
|
||
|
structures to be built. \[7\] More recently, single units that combine
|
||
|
antenna, wireless card and processor have become available. These are
|
||
|
very convenient for installation. To build a relay, one simply connects
|
||
|
such units together with ethernet cables that carry both signal and
|
||
|
power. \[6\] The units can be mounted in towers or slim masts, given
|
||
|
that they offer little windload. \[3\] Examples of suppliers of long
|
||
|
range WiFi components are [Ubiquity](https://www.ubnt.com/),
|
||
|
[Alvarion](http://www.alvarion.com/) and
|
||
|
[MikroTik](http://www.mikrotik.com/), and
|
||
|
[simpleWiFi](https://www.simplewifi.com/).
|
||
|
|
||
|
Long Range WiFi makes use of unlicensed spectrum and offers high
|
||
|
bandwidth, low capital costs, easy installation, and low power
|
||
|
requirements.
|
||
|
|
||
|
Long range WiFi also has low operational costs due to low power
|
||
|
requirements. A typical mast installation consisting of two long
|
||
|
distance links and one or two wireless cards for local distribution
|
||
|
consumes around 30 watts. \[6,12\] In several low-tech networks, nodes
|
||
|
are entirely powered by solar panels and batteries. Another important
|
||
|
advantage of long range WiFi is that it makes use of unlicensed spectrum
|
||
|
(2.4 and 5 GHz), and thus avoids negotiations with telecom operators and
|
||
|
government. This adds to the cost advantage and allows basically anyone
|
||
|
to start a WiFi-based long distance network. \[9\]
|
||
|
|
||
|
****Long Range WiFi Networks in Poor Countries****
|
||
|
|
||
|
The first long range WiFi networks were set up ten to fifteen years ago.
|
||
|
In poor countries, two main types have been built. The first is aimed at
|
||
|
providing internet access to people in remote villages. An example is
|
||
|
the Akshaya network in India, which covers the entire Kerala State and
|
||
|
is one of the largest wireless networks in the world. The infrastructure
|
||
|
is built around approximately 2,500 \"computer access centers\", which
|
||
|
are open to the local population \-- direct ownership of computers is
|
||
|
minimal in the region. \[13\]
|
||
|
|
||
|
Another example, also in India, are the AirJaldi networks which provide
|
||
|
internet access to approximately 20,000 users in six states, all in
|
||
|
remote regions and on difficult terrain. Most nodes in this network are
|
||
|
solar-powered and the distance between them can range up to 50 km or
|
||
|
more. \[14\] In some African countries, local WiFi-networks distribute
|
||
|
internet access from a satellite gateway. \[15,16\]
|
||
|
|
||
|
A node in the AirJaldi network. Picture: AirJaldi.
|
||
|
|
||
|
A second type of long distance WiFi network in poor countries is aimed
|
||
|
at providing telemedicine to remote communities. In remote regions,
|
||
|
health care is often provided through health posts scarcely equipped and
|
||
|
attended by health technicians who are barely trained. \[17\] Long-range
|
||
|
WiFi networks can connect urban hospitals with these outlying health
|
||
|
posts, allowing doctors to remotely support health technicians using
|
||
|
high-resolution file transfers and real-time communication tools based
|
||
|
on voice and video.
|
||
|
|
||
|
An example is the link between Cabo Pantoja and Iquitos in the Loreto
|
||
|
province in Peru, which was established in 2007. The 450 km network
|
||
|
consists of 17 towers which are 16 to 50 km apart. The line connects 15
|
||
|
medical outposts in remote villages with the main hospital in Iquitos
|
||
|
and is aimed at remote diagnosis of patients. \[17,18\] All equipment is
|
||
|
powered by solar panels. \[18,19\] Other succesful examples of long
|
||
|
range WiFi telemedicine networks have been built in India, Malawi and
|
||
|
Ghana. \[20,21\]
|
||
|
|
||
|
****WiFi-Based Community Networks in Europe****
|
||
|
|
||
|
The low-tech networks in poor countries are set up by NGO\'s,
|
||
|
governments, universities or businesses. In contrast, most of the
|
||
|
WiFi-based long distance networks in remote regions of rich countries
|
||
|
are so-called \"community networks\": the users themselves build, own,
|
||
|
power and maintain the infrastructure. Similar to the shared wireless
|
||
|
approach in cities, reciprocal resource sharing forms the basis of these
|
||
|
networks: participants can set up their own node and connect to the
|
||
|
network (for free), as long as their node also allows traffic of other
|
||
|
members. Each node acts as a WiFi routing device that provides IP
|
||
|
forwarding services and a data link to all users and nodes connected to
|
||
|
it. \[8,22\]
|
||
|
|
||
|
In a community network, the users themselves build, own, power and
|
||
|
maintain the infrastructure.
|
||
|
|
||
|
Consequently, with each new user, the network becomes larger. There is
|
||
|
no a-priori overall planning. A community network grows bottom-up,
|
||
|
driven by the needs of its users, as nodes and links are added or
|
||
|
upgraded following demand patterns. The only consideration is to connect
|
||
|
a node from a new participant to an existing one. As a node is powered
|
||
|
on, it discovers it neighbours, attributes itself a unique IP adress,
|
||
|
and then establishes the most appropriate routes to the rest of the
|
||
|
network, taking into account the quality of the links. Community
|
||
|
networks are open to participation to everyone, sometimes according to
|
||
|
an open peering agreement. \[8,9,19,22\]
|
||
|
|
||
|
Wireless links in the Spanish Guifi network.
|
||
|
[Credit](https://iuliinet.github.io/presentazione_ottobre_2014/img/barcellona.jpg).
|
||
|
|
||
|
Despite the lack of reliable statistics, community networks seem to be
|
||
|
rather succesful, and there are several large ones in Europe, such as
|
||
|
[Guifi.net](https://guifi.net/) (Spain), [Athens Wireless Metropolitan
|
||
|
Network](http://www.awmn.gr/content.php?s=ce506a41ab245641d6934638c6f6f107)
|
||
|
(Greece), [FunkFeuer](http://www.funkfeuer.at/) (Austria), and
|
||
|
[Freifunk](https://freifunk.net/en/) (Germany). \[8,22,23,24\] The
|
||
|
Spanish network is the largest WiFi-based long distance network in the
|
||
|
world with more than 50,000 kilometres of links, although a small part
|
||
|
is based on optic fibre links. Most of it is located in the Catalan
|
||
|
Pyrenees, one of the least populated areas in Spain. The network was
|
||
|
initiated in 2004 and now has close to 30,000 nodes, up from 17,000 in
|
||
|
2012. \[8,22\]
|
||
|
|
||
|
Guifi.net provides internet access to individuals, companies,
|
||
|
administrations and universities. In principle, the network is
|
||
|
installed, powered and maintained by its users, although volunteer teams
|
||
|
and even commercial installers are present to help. Some nodes and
|
||
|
backbone upgrades have been succesfully crowdfunded by indirect
|
||
|
beneficiaries of the network. \[8,22\]
|
||
|
|
||
|
****Performance of Low-tech Networks****
|
||
|
|
||
|
So how about the performance of low-tech networks? What can you do with
|
||
|
them? The available bandwidth per user can vary enormously, depending on
|
||
|
the bandwidth of the gateway node(s) and the number of users, among
|
||
|
other factors. The long-distance WiFi networks aimed at telemedicine in
|
||
|
poor countries have few users and a good backhaul, resulting in high
|
||
|
bandwidth (+ 40 Mbps). This gives them a similar performance to fibre
|
||
|
connections in the developed world. A study of (a small part of) the
|
||
|
Guifi.net community network, which has dozens of gateway nodes and
|
||
|
thousands of users, showed an average throughput of 2 Mbps, which is
|
||
|
comparable to a relatively slow DSL connection. Actual throughput per
|
||
|
user varies from 700 kbps to 8 Mbps. \[25\]
|
||
|
|
||
|
The available bandwidth per user can vary enormously, depending on the
|
||
|
bandwidth of the gateway node(s) and the number of users, among other
|
||
|
factors
|
||
|
|
||
|
However, the low-tech networks that distribute internet access to a
|
||
|
large user base in developing countries can have much more limited
|
||
|
bandwidth per user. For example, a university campus in Kerala (India)
|
||
|
uses a 750 kbps internet connection that is shared across 3,000 faculty
|
||
|
members and students operating from 400 machines, where during peak
|
||
|
hours nearly every machine is being used.
|
||
|
|
||
|
Therefore, the worst-case average bandwidth available per machine is
|
||
|
approximately 1.9 kbps, which is slow even in comparison to a dial-up
|
||
|
connection (56 kbps). And this can be considered a really good
|
||
|
connectivity compared to typical rural settings in poor countries.
|
||
|
\[26\] To make matters worse, such networks often have to deal with an
|
||
|
intermittent power supply.
|
||
|
|
||
|
Under these circumstances, even the most common internet applications
|
||
|
have poor performance, or don\'t work at all. The communication model of
|
||
|
the internet is based on a set of network assumptions, called the TCP/IP
|
||
|
protocol suite. These include the existence of a bi-directional
|
||
|
end-to-end path between the source (for example a website\'s server) and
|
||
|
the destination (the user\'s computer), short round-trip delays, and low
|
||
|
error rates.
|
||
|
|
||
|
Many low-tech networks in poor countries do not comform to these
|
||
|
assumptions. They are characterized by intermittent connectivity or
|
||
|
\"network partitioning\" \-- the absence of an end-to-end path between
|
||
|
source and destination \-- long and variable delays, and high error
|
||
|
rates. \[21,27,28\]
|
||
|
|
||
|
****Delay-Tolerant Networks****
|
||
|
|
||
|
Nevertheless, even in such conditions, the internet could work perfectly
|
||
|
fine. The technical issues can be solved by moving away from the
|
||
|
always-on model of traditional networks, and instead design networks
|
||
|
based upon asynchronous communication and intermittent connectivity.
|
||
|
These so-called \"delay-tolerant networks\" (DTNs) have their own
|
||
|
specialized protocols overlayed on top of the lower protocols and do not
|
||
|
utilize TCP. They overcome the problems of intermittent connectivity and
|
||
|
long delays by using store-and-forward message switching.
|
||
|
|
||
|
Information is forwarded from a storage place on one node to a storage
|
||
|
place on another node, along a path that *eventually* reaches its
|
||
|
destination. In contrast to traditional internet routers, which only
|
||
|
store incoming packets for a few milliseconds on memory chips, the nodes
|
||
|
of a delay-tolerant network have persistent storage (such as hard disks)
|
||
|
that can hold information indefinitely. \[27,28\]
|
||
|
|
||
|
Delay-tolerant networks combine well with renewable energy: solar panels
|
||
|
or wind turbines could power network nodes only when the sun shines or
|
||
|
the wind blows, eliminating the need for energy storage.
|
||
|
|
||
|
Delay-tolerant networks don\'t require an end-to-end path between source
|
||
|
and destination. Data is simply transferred from node to node. If the
|
||
|
next node is unavailable because of long delays or a power outage, the
|
||
|
data is stored on the hard disk until the node becomes available again.
|
||
|
While it might take a long time for data to travel from source to
|
||
|
destination, a delay-tolerant network ensures that it will eventually
|
||
|
arrive.
|
||
|
|
||
|
Delay-tolerant networks further decrease capital costs and energy use,
|
||
|
leading to the most efficient use of scarce resources. They keep working
|
||
|
with an intermittent energy supply and they combine well with renewable
|
||
|
energy sources: solar panels or wind turbines could power network nodes
|
||
|
only when the sun shines or the wind blows, eliminating the need for
|
||
|
energy storage.
|
||
|
|
||
|
****Data Mules****
|
||
|
|
||
|
Delay-tolerant networking can take surprising forms, especially when
|
||
|
they take advantage of some non-traditional means of communication, such
|
||
|
as \"data mules\". \[11,29\] In such networks, conventional
|
||
|
transportation technologies \-- buses, cars, motorcycles, trains, boats,
|
||
|
airplanes \-- are used to ferry messages from one location to another in
|
||
|
a store-and-forward manner.
|
||
|
|
||
|
Examples are DakNet and KioskNet, which use buses as data mules.
|
||
|
\[30-34\] In many developing regions, rural bus routes regularly visit
|
||
|
villages and towns that have no network connectivity. By equipping each
|
||
|
vehicle with a computer, a storage device and a mobile WiFi-node on the
|
||
|
one hand, and by installing a stationary WiFi-node in each village on
|
||
|
the other hand, the local transport infrastructure can substitute for a
|
||
|
wireless internet link. \[11\]
|
||
|
|
||
|
Picture: AirJaldi.
|
||
|
|
||
|
Outgoing data (such as sent emails or requests for webpages) is stored
|
||
|
on local computers in the village until the bus comes withing range. At
|
||
|
this point, the fixed WiFi-node of the local computer automatically
|
||
|
transmits the data to the mobile WiFi-node of the bus. Later, when the
|
||
|
bus arrives at a hub that is connected to the internet, the outgoing
|
||
|
data is transmitted from the mobile WiFi-node to the gateway node, and
|
||
|
then to the internet. Data sent to the village takes the opposite route.
|
||
|
The bus \-- or data \-- driver doesn\'t require any special skills and
|
||
|
is completely oblivious to the data transfers taking place. He or she
|
||
|
does not need to do anything other than come in range of the nodes.
|
||
|
\[30,31\]
|
||
|
|
||
|
In a data mules network, the local transport infrastructure substitutes
|
||
|
for a wireless internet link.
|
||
|
|
||
|
The use of data mules offers some extra advantages over more
|
||
|
\"sophisticated\" delay-tolerant networks. A \"drive-by\" WiFi network
|
||
|
allows for small, low-cost and low-power radio devices to be used, which
|
||
|
don\'t require line of sight and consequently no towers \-- further
|
||
|
lowering capital costs and energy use compared to other low-tech
|
||
|
networks. \[30,31,32\]
|
||
|
|
||
|
The use of short-distance WiFi-links also results in a higher bandwidth
|
||
|
compared to long-distance WiFi-links, which makes data mules better
|
||
|
suited to transfer larger files. On average, 20 MB of data can be moved
|
||
|
in each direction when a bus passes a fixed WiFi-node. \[30,32\] On the
|
||
|
other hand, latency (the time interval between sending and receiving
|
||
|
data) is usually higher than on long-range WiFi-links. A single bus
|
||
|
passing by a village once a day gives a latency of 24 hours.
|
||
|
|
||
|
****Delay-Tolerant Software****
|
||
|
|
||
|
Obviously, a delay-tolerant network (DTN) \-- whatever its form \-- also
|
||
|
requires new software: applications that function without a connected
|
||
|
end-to-end networking path. \[11\] Such custom applications are also
|
||
|
useful for synchronous, low bandwidth networks. Email is relatively easy
|
||
|
to adapt to intermittent connectivity, because it\'s an asynchronous
|
||
|
communication method by itself. A DTN-enabled email client stores
|
||
|
outgoing messages until a connection is available. Although emails may
|
||
|
take longer to reach their destination, the user experience doesn\'t
|
||
|
really change.
|
||
|
|
||
|
A Freifunk WiFi-node is installed in Berlin, Germany. Picture:[
|
||
|
Wikipedia
|
||
|
Commons](https://upload.wikimedia.org/wikipedia/commons/5/51/Freifunk-Initiative_in_Berlin-Kreuzberg.jpg).
|
||
|
|
||
|
Browsing and searching the web requires more adaptations. For example,
|
||
|
most search engines optimize for speed, assuming that a user can quickly
|
||
|
look through the returned links and immediately run a second modified
|
||
|
search if the first result is inadequate. However, in intermittent
|
||
|
networks, multiple rounds of interactive search would be impractical.
|
||
|
\[26,35\] Asynchronous search engines optimize for bandwith rather than
|
||
|
response time. \[26,30,31,35,36\] For example, RuralCafe desynchronizes
|
||
|
the search process by performing many search tasks in an offline manner,
|
||
|
refining the search request based on a database of similar searches. The
|
||
|
actual retrieval of information using the network is only done when
|
||
|
absolutely necessary.
|
||
|
|
||
|
Many internet applications could be adapted to intermittent networks,
|
||
|
such as webbrowsing, email, electronic form filling, interaction with
|
||
|
e-commerce sites, blogsoftware, large file downloads, or social media.
|
||
|
|
||
|
Some DTN-enabled browsers download not only the explicitly requested
|
||
|
webpages but also the pages that are linked to by the requested pages.
|
||
|
\[30\] Others are optimized to return low-bandwidth results, which are
|
||
|
achieved by filtering, analysis, and compression on the server site. A
|
||
|
similar effect can be achieved through the use of a service like
|
||
|
[Loband](http://www.loband.org/loband/), which strips webpages of
|
||
|
images, video, advertisements, social media buttons, and so on, merely
|
||
|
presenting the textual content. \[26\]
|
||
|
|
||
|
Browsing and searching on intermittent networks can also be improved by
|
||
|
local caching (storing already downloaded pages) and prefetching
|
||
|
(downloading pages that might be retrieved in the future). \[206\] Many
|
||
|
other internet applications could also be adapted to intermittent
|
||
|
networks, such as electronic form filling, interaction with e-commerce
|
||
|
sites, blogsoftware, large file downloads, social media, and so on.
|
||
|
\[11,30\] All these applications would remain possible, though at lower
|
||
|
speeds.
|
||
|
|
||
|
****Sneakernets****
|
||
|
|
||
|
Obviously, real-time applications such as internet telephony, media
|
||
|
streaming, chatting or videoconferencing are impossible to adapt to
|
||
|
intermittent networks, which provide only asynchronous communication.
|
||
|
These applications are also difficult to run on synchronous networks
|
||
|
that have limited bandwidth. Because these are the applications that are
|
||
|
in large part responsible for the growing energy use of the internet,
|
||
|
one could argue that their incompatibility with low-tech networks is
|
||
|
actually a good thing (see the [previous
|
||
|
article](https://www.lowtechmagazine.com/2015/10/can-the-internet-run-on-renewable-energy.html)).
|
||
|
|
||
|
Furthermore, many of these applications could be organized in different
|
||
|
ways. While real-time voice or video conversations won\'t work, it\'s
|
||
|
perfectly possible to send and receive voice or video messages. And
|
||
|
while streaming media can\'t happen, downloading music albums and video
|
||
|
remains possible. Moreover, these files could be \"transmitted\" by the
|
||
|
most low-tech internet technology available: a sneakernet. In a
|
||
|
sneakernet, digital data is \"wirelessly\" transmitted using a storage
|
||
|
medium such as a hard disk, a USB-key, a flash card, or a CD or DVD.
|
||
|
Before the arrival of the internet, all computer files were exchanged
|
||
|
via a sneakernet, using tape or floppy disks as a storage medium.
|
||
|
|
||
|
Stuffing a cargo train full of digital storage media would beat any
|
||
|
digital network in terms of speed, cost and energy efficiency. Picture:
|
||
|
Wikipedia Commons.
|
||
|
|
||
|
Just like a data mules network, a sneakernet involves a vehicle, a
|
||
|
messenger on foot, or an animal (such as a [carrier
|
||
|
pigeon](https://www.lowtechmagazine.com/2009/02/sneakernet-beats-internet.html)).
|
||
|
However, in a sneakernet there is no automatic data transfer between the
|
||
|
mobile node (for instance, a vehicle) and the stationary nodes (sender
|
||
|
and recipient). Instead, the data first have to be transferred from the
|
||
|
sender\'s computer to a portable storage medium. Then, upon arrival, the
|
||
|
data have to be transferred from the portable storage medium to the
|
||
|
receiver\'s computer. \[30\] A sneakernet thus requires manual
|
||
|
intervention and this makes it less convenient for many internet
|
||
|
applications.
|
||
|
|
||
|
There are exceptions, though. For example, a movie doesn\'t have to be
|
||
|
transferred to the hard disk of your computer in order to watch it. You
|
||
|
play it straight from a portable hard disk or slide a disc into the
|
||
|
DVD-player. Moreover, a sneakernet also offers an important advantage:
|
||
|
of all low-tech networks, it has the most bandwidth available. This
|
||
|
makes it perfectly suited for the distribution of large files such as
|
||
|
movies or computer games. In fact, when very large files are involved, a
|
||
|
sneakernet even beats the fastest fibre internet connection. At lower
|
||
|
internet speeds, sneakernets can be advantageous for much smaller files.
|
||
|
|
||
|
Technological progress will not lower the advantage of a sneakernet.
|
||
|
Digital storage media evolve at least as fast as internet connections
|
||
|
and they both improve communication in an equal way.
|
||
|
|
||
|
****Resilient Networks****
|
||
|
|
||
|
While most low-tech networks are aimed at regions where the alternative
|
||
|
is often no internet connection at all, their usefulness for
|
||
|
well-connected areas cannot be overlooked. The internet as we know it in
|
||
|
the industrialized world is a product of an abundant energy supply, a
|
||
|
robust electricity infrastructure, and sustained economic growth. This
|
||
|
\"high-tech\" internet might offer some fancy advantages over the
|
||
|
low-tech networks, but it cannot survive if these conditions change.
|
||
|
This makes it extremely vulnerable.
|
||
|
|
||
|
The internet as we know it in the industrialized world is a product of
|
||
|
an abundant energy supply, a robust electricity infrastructure, and
|
||
|
sustained economic growth. It cannot survive if these conditions change.
|
||
|
|
||
|
Depending on their level of resilience, low-tech networks can remain in
|
||
|
operation when the supply of fossil fuels is interrupted, when the
|
||
|
electricity infrastructure deteriorates, when the economy grinds to a
|
||
|
halt, or if other calamities should hit. Such a low-tech internet would
|
||
|
allow us to surf the web, send and receive e-mails, shop online, share
|
||
|
content, and so on. Meanwhile, data mules and sneakernets could serve to
|
||
|
handle the distribution of large files such as videos. Stuffing a cargo
|
||
|
vessel or a train full of digital storage media would beat any digital
|
||
|
network in terms of speed, cost and energy efficiency. And if such a
|
||
|
transport infrastructure would no longer be available, we could still
|
||
|
rely on messengers on foot, [cargo
|
||
|
bikes](https://www.lowtechmagazine.com/2014/05/modular-cargo-cycles.html)
|
||
|
and [sailing vessels](https://www.lowtechmagazine.com/sailing-ships/).
|
||
|
|
||
|
Such a hybrid system of online and offline applications would remain a
|
||
|
very powerful communication network \-- unlike anything we had even in
|
||
|
the late twentieth century. Even if we envision a doom scenario in which
|
||
|
the wider internet infrastructure would disintegrate, isolated low-tech
|
||
|
networks would still be very useful local and regional communication
|
||
|
technologies. Furthermore, they could obtain content from other remote
|
||
|
networks through the exchange of portable storage media. The internet,
|
||
|
it appears, can be as low-tech or high-tech as we can afford it to be.
|
||
|
|
||
|
Kris De Decker (edited by [Jenna
|
||
|
Collett](https://www.linkedin.com/pub/jenna-collett/1a/925/b3))
|
||
|
|
||
|
This article has been translated into
|
||
|
[Spanish](https://solar.lowtechmagazine.com/es/2015/10/how-to-build-a-low-tech-internet.html).
|
||
|
|
||
|
****Sources & Notes:****
|
||
|
|
||
|
DIY: [Wireless networking in the developing
|
||
|
world](http://wndw.net/book.html#readBook) (Third Edition) is a free
|
||
|
book about designing, implementing and maintaining low-cost wireless
|
||
|
networks. Available in English, French, and Spanish.
|
||
|
|
||
|
\[1\] [Connecting the unwired world with balloons, satellites, lasers &
|
||
|
drones](https://tech.slashdot.org/story/15/09/03/214256/connecting-the-unwired-world-with-balloons-satellites-lasers-drones),
|
||
|
Slashdot, 2015
|
||
|
|
||
|
\[2\] [A QoS-aware dynamic bandwidth allocation scheme for multi-hop
|
||
|
WiFi-based long distance
|
||
|
networks](https://link.springer.com/article/10.1186%2Fs13638-015-0352-z#/page-1),
|
||
|
Iftekhar Hussain et al., 2015
|
||
|
|
||
|
\[3\] [Long-distance, Low-Cost Wireless Data
|
||
|
Transmission](http://www.ursi.org/files/RSBissues/RSB_339_2011_12.pdf)
|
||
|
(PDF), Ermanno Pietrosemoli, 2011
|
||
|
|
||
|
\[4\] This link could only be established thanks to the height of the
|
||
|
endpoints (4,200 and 1,500 km) and the flatness of the middle ground.
|
||
|
The curvature of the Earth makes longer point-to-point WiFi-links
|
||
|
difficult to achieve because line of sight between two points is
|
||
|
required.
|
||
|
|
||
|
\[5\] Radio waves occupy a volume around the optical line, which must be
|
||
|
unemcumbered from obstacles. This volume is known as the Fresnel
|
||
|
ellipsoid and its size grows with the distance between the two end
|
||
|
points and with the wavelength of the signal, which is in turn inversely
|
||
|
proportional to the frequency. Thus, it is required to leave extra
|
||
|
\"elbow room\" for the Fresnel zone. \[9\]
|
||
|
|
||
|
\[6\] [A Brief History of the Tegola
|
||
|
Project](http://www.tegola.org.uk/tegola-history.html), Tegola Project,
|
||
|
retrieved October 2015
|
||
|
|
||
|
\[7\] [WiLDNet: Design and Implementation of High Performance WiFi based
|
||
|
Long Distance
|
||
|
Networks](http://tier.cs.berkeley.edu/docs/wireless/wild_multihop.pdf)
|
||
|
(PDF), Rabin Patra et al., 2007
|
||
|
|
||
|
\[8\] [Topology Patterns of a Community Network:
|
||
|
Guifi.net](http://dsg.ac.upc.edu/sites/default/files/1569633605.pdf)
|
||
|
(PDF), Davide Vega et al., 2012
|
||
|
|
||
|
\[9\] [Global Access to the Internet for All, internet
|
||
|
draft](https://trac.tools.ietf.org/group/irtf/trac/wiki/gaia), Internet
|
||
|
Engineering Task Force (IETF), 2015
|
||
|
|
||
|
\[10\] This is what happened to Afghanistan\'s JLINK network when
|
||
|
[funding for the network\'s satellite link ran dry in
|
||
|
2012](https://www.wired.com/2012/05/jlink/).
|
||
|
|
||
|
\[11\] [The case for technology in developing
|
||
|
regions](https://www.cs.cmu.edu/~mattkam/lab/publications/Computer2005.pdf)
|
||
|
(PDF), Eric Brewer et al., 2005
|
||
|
|
||
|
\[12\] [Beyond Pilots: Keeping Rural Wireless Networks
|
||
|
Alive](https://www.usenix.org/legacy/event/nsdi08/tech/full_papers/surana/surana.pdf)
|
||
|
(PDF), Sonesh Surana et al., 2008
|
||
|
|
||
|
\[13\] <http://www.akshaya.kerala.gov.in/>
|
||
|
|
||
|
\[14\] <http://main.airjaldi.com/>
|
||
|
|
||
|
\[15\] [VillageCell: Cost Effective Cellular Connectivity in Rural
|
||
|
Areas](http://www.cs.bham.ac.uk/~pejovicv/docs/Anand12ICTD.pdf) (PDF),
|
||
|
Abhinav Anand et al., 2012
|
||
|
|
||
|
\[16\] [Deployment and Extensio of a Converged WiMAX/WiFi Network for
|
||
|
Dwesa Community Area South
|
||
|
Africa](http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.452.7357&rep=rep1&type=pdf)
|
||
|
(PDF), N. Ndlovu et al., 2009
|
||
|
|
||
|
\[17\] \"[A telemedicine network optimized for long distances in the
|
||
|
Amazonian jungle of
|
||
|
Peru](http://www.ehas.org/wp-content/uploads/2012/01/Extremecomm_sig_ISBN.pdf)\"
|
||
|
(PDF), Carlos Rey-Moreno, ExtremeCom \'11, September 2011
|
||
|
|
||
|
\[18\] \"[Telemedicine networks of EHAS Foundation in Latin
|
||
|
America](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4197650/)\",
|
||
|
Ignacio Prieto-Egido et al., in \"Frontiers in Public Health\", October
|
||
|
15, 2014.
|
||
|
|
||
|
\[19\] \"[The design of a wireless solar-powered router for rural
|
||
|
environments isolated from health
|
||
|
facilities](https://eciencia.urjc.es/bitstream/handle/10115/2293/THE%20DESIGN%20OF%20A%20WIRELESS%20SOLAR-POWERED-2008.pdf?sequence=1)\"
|
||
|
(PDF), Francisco Javier Simo Reigadas et al., in \"IEEE Wireless
|
||
|
Communications\", June 2008.
|
||
|
|
||
|
\[20\] [On a long wireless link for rural telemedicine in
|
||
|
Malawi](http://users.ictp.it/~mzennaro/Malawi.pdf) (PDF), M. Zennaro et
|
||
|
al., 2008
|
||
|
|
||
|
\[21\] [A Survey of Delay- and Disruption-Tolerant Networking
|
||
|
Applications](http://www.jie-online.org/index.php/jie/article/view/91),
|
||
|
Artemios G. Voyiatzis, 2012
|
||
|
|
||
|
\[22\] [Supporting Cloud Deployment in the Guifi Community
|
||
|
Network](https://www.sics.se/~amir/files/download/papers/guifi.pdf)
|
||
|
(PDF), Roger Baig et al., 2013
|
||
|
|
||
|
\[23\] [A Case for Research with and on Community
|
||
|
Networks](http://www.sigcomm.org/sites/default/files/ccr/papers/2013/July/2500098-2500108.pdf)
|
||
|
(PDF), Bart Braem et.al, 2013
|
||
|
|
||
|
\[24\] There are smaller networks in Scotland
|
||
|
([Tegola](http://www.tegola.org.uk/)), Slovenia ([wlan
|
||
|
slovenija](https://wlan-si.net/)), Belgium ([Wireless
|
||
|
Antwerpen](http://www.wirelessantwerpen.be/)), and the Netherlands
|
||
|
([Wireless Leiden](https://www.wirelessleiden.nl/)), among others.
|
||
|
Australia has [Melbourne Wireless](http://melbourne.wireless.org.au/).
|
||
|
In Latin America, numerous examples exists, such as [Bogota
|
||
|
Mesh](https://www.facebook.com/BogotaMesh) (Colombia) and [Monte Video
|
||
|
Libre](http://picandocodigo.net/2008/montevideolibre-redes-libres-en-montevideo/)
|
||
|
(Uruguay). Some of these networks are interconnected. This is the case
|
||
|
for the Belgian and Dutch community networks, and for the Slovenian and
|
||
|
Austrian networks. \[8,22,23\]
|
||
|
|
||
|
\[25\] [Proxy performance analysis in a community wireless
|
||
|
network](http://upcommons.upc.edu/handle/2099.1/19710), Pablo Pitarch
|
||
|
Miguel, 2013
|
||
|
|
||
|
\[26\] [RuralCafe: Web Search in the Rural Developing
|
||
|
World](http://www.ambuehler.ethz.ch/CDstore/www2009/proc/docs/p411.pdf)
|
||
|
(PDF), Jay Chen et al., 2009
|
||
|
|
||
|
\[27\] [A Delay-Tolerant Network Architecture for Challenged
|
||
|
Networks](http://www.kevinfall.com/seipage/papers/p27-fall.pdf) (PDF),
|
||
|
Kevin Fall, 2003
|
||
|
|
||
|
\[28\] [Delay- and Disruption-Tolerant Networks (DTNs) \-- A Tutorial
|
||
|
(version
|
||
|
2.0)](http://ipnsig.org/wp-content/uploads/2012/07/DTN_Tutorial_v2.04.pdf)
|
||
|
(PDF), Forrest Warthman, 2012
|
||
|
|
||
|
\[29\] [Healthcare Supported by Data Mule Networks in Remote Communities
|
||
|
of the Amazon
|
||
|
Region](http://www.hindawi.com/journals/isrn/2014/730760/), Mauro
|
||
|
Margalho Coutinho et al., 2014
|
||
|
|
||
|
\[30\] [First Mile Solutions\' Daknet Takes Rural Communities
|
||
|
Online](http://www.firstmilesolutions.com/documents/FMS_Case_Study.pdf)
|
||
|
(PDF), Carol Chyau and Jean-Francois Raymond, 2005
|
||
|
|
||
|
\[31\] [DakNet: A Road to Universal Broadband
|
||
|
Connectivity](http://courses.media.mit.edu/2003fall/de/DakNet-Case.pdf)
|
||
|
(PDF), Amir Alexander Hasson et al., 2003
|
||
|
|
||
|
\[32\] [DakNet: Architecture and Connectivity in Developing
|
||
|
Nations](http://ijpret.com/publishedarticle/2015/4/IJPRET%20-%20ECN%20115.pdf)
|
||
|
(PDF), Madhuri Bhole, 2015
|
||
|
|
||
|
\[33\] [Delay Tolerant Networks and Their
|
||
|
Applications](http://www.citeulike.org/user/tnhh/article/13517347),
|
||
|
Longxiang Gao et al., 2015
|
||
|
|
||
|
\[34\] [Low-cost communication for rural internet kiosks using
|
||
|
mechanical
|
||
|
backhaul](https://people.csail.mit.edu/matei/papers/2006/mobicom_kiosks.pdf),
|
||
|
A. Seth et al., 2006
|
||
|
|
||
|
\[35\] [Searching the World Wide Web in Low-Connectivity
|
||
|
Communities](http://tek.sourceforge.net/papers/tek-www02.pdf) (PDF),
|
||
|
William Thies et al., 2002
|
||
|
|
||
|
\[36\] [Slow Search: Information Retrieval without Time
|
||
|
Constraints](https://www.cs.cmu.edu/~yubink/hcir2013.pdf) (PDF), Jaime
|
||
|
Teevan, 2013
|
||
|
|
||
|
\[37\] [Potential for Collaborative Caching and Prefetching in
|
||
|
Largely-Disconnected
|
||
|
Villages](http://mrmgroup.cs.princeton.edu/papers/isaacman-winsdr503.pdf)
|
||
|
(PDF), Sibren Isaacman et al., 2008
|
||
|
|
||
|
--
|
||
|
--
|
||
|
|
||
|
Posted on October 26, 2015 at 12:26 AM in [Access to
|
||
|
information](https://www.lowtechmagazine.com/copyright_and_access_to_information/),
|
||
|
[Communications](https://www.lowtechmagazine.com/communications/),
|
||
|
[Cover story](https://www.lowtechmagazine.com/cover-story/),
|
||
|
[DIY](https://www.lowtechmagazine.com/diy/),
|
||
|
[Internet](https://www.lowtechmagazine.com/internet/), [Wireless
|
||
|
technology](https://www.lowtechmagazine.com/wireless_technology/) \|
|
||
|
[Permalink](https://www.lowtechmagazine.com/2015/10/how-to-build-a-low-tech-internet.html)
|