Windows

decentralized network. Decentralized and distributed databases

And each node (peer) is both a client and performs the functions of a server. In contrast to the client-server architecture, such an organization allows the network to remain operational with any number and any combination of available nodes. The members of the network are peers.

History

The phrase "peer-to-peer" was first used in 1984 when developing the IBM Advanced Peer to Peer Networking (APPN) architecture.

Peer-to-peer device

There are a number of machines on the network, each of which can communicate with any of the others. Each of these machines can send requests to other machines for some resources within this network and thus act as a client. As a server, each machine must be able to process requests from other machines on the network, send out what was requested. Each machine must also perform some auxiliary and administrative functions (for example, keep a list of other known "neighbors" machines and keep it up to date).

Any member of this network does not guarantee its presence on a permanent basis. It can appear and disappear at any time. But when a certain critical network size is reached, there comes a moment when there are many servers with the same functions in the network at the same time.

Private P2P networks

Partially decentralized (hybrid) networks

In addition to pure P2P networks, there are so-called hybrid networks in which there are servers used to coordinate work, search or provide information about existing network machines and their status (on-line, off-line, etc.). Hybrid networks combine the speed of centralized networks and the reliability of decentralized ones thanks to hybrid schemes with independent indexing servers that synchronize information with each other. If one or more servers fail, the network continues to function. Partially decentralized networks include eDonkey, BitTorrent, Direct Connect, The Onion Router.

peer-to-peer file sharing network

Many files distributed in such networks, which are not legally free for distribution, are distributed in them without the permission of the copyright holders. Video publishing and record companies claim that this results in significant lost profits. Adding problems to them is the fact that it is technically impossible to stop the distribution of a file in a decentralized network - this will require physically disconnecting all the machines on which this file is located from the network, and there can be very, very many such machines (see above) - depending on the popularity of a file, their number can reach several hundred thousand. Recently, video publishers and record companies have begun to sue individual users of such networks, accusing them of illegally distributing music and video.

Peer-to-Peer Distributed Computing Networks

The technology of peer-to-peer networks (not subject to quasi-synchronous calculus) is also used for distributed computing. They allow in a relatively short time to perform a truly huge amount of calculations, which even on supercomputers would require, depending on the complexity of the task, many years and even centuries of work. This performance is achieved due to the fact that some global task is divided into a large number of blocks that are simultaneously executed by hundreds of thousands of computers participating in the project. One example of this use of peer-to-peer networks was demonstrated by Sony on the Sony PlayStation game consoles.

Peer-to-peer payment systems

Decentralized payment systems called cryptocurrencies. The main idea of their developers is that modern payment systems are imperfect and depend on the will of high-ranking officials. Decentralized systems based on p2p technologies are a fairer means of mutual settlements between users.

Other decentralized services

peer-to-peer broadcasting

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Notes

An excerpt characterizing the peer-to-peer network

Count Turen led him into a large waiting room, where many generals, chamberlains and Polish magnates were waiting, many of whom Balashev had seen at the court of the Russian emperor. Duroc said that Emperor Napoleon would receive the Russian general before his walk.
After several minutes of waiting, the chamberlain on duty went out into the large reception room and, bowing politely to Balashev, invited him to follow him.
Balashev entered a small reception room, from which there was one door leading to an office, the same office from which the Russian emperor sent him. Balashev stood for one minute or two, waiting. Hasty footsteps sounded outside the door. Both halves of the door quickly opened, the chamberlain who had opened it respectfully stopped, waiting, everything was quiet, and other, firm, resolute steps sounded from the office: it was Napoleon. He has just finished his riding toilet. He was in a blue uniform, open over a white waistcoat, descending on a round stomach, in white leggings, tight-fitting fat thighs of short legs, and in over the knee boots. His short hair, obviously, had just been combed, but one strand of hair went down over the middle of his wide forehead. His plump white neck protruded sharply from behind the black collar of his uniform; he smelled of cologne. On his youthful full face with a protruding chin was an expression of gracious and majestic imperial greeting.
He went out, trembling rapidly at every step, and throwing back his head a little. His whole stout, short figure, with broad, thick shoulders and an involuntarily protruding belly and chest, had that representative, portly appearance that people of forty years of age who live in the hall have. In addition, it was evident that he was in the best mood that day.
He nodded his head in response to Balashev's low and respectful bow, and, going up to him, immediately began to speak like a man who values every minute of his time and does not condescend to prepare his speeches, but is confident that he will always say well and what to say.
Hello, General! - he said. - I received the letter from Emperor Alexander, which you delivered, and I am very glad to see you. He looked into Balashev's face with his large eyes and immediately began to look ahead past him.
It was obvious that he was not at all interested in the personality of Balashev. It was evident that only what was going on in his soul was of interest to him. Everything that was outside of him did not matter to him, because everything in the world, as it seemed to him, depended only on his will.
“I don’t want and didn’t want war,” he said, “but I was forced into it. Even now (he said this word with emphasis) I am ready to accept all the explanations that you can give me. - And he clearly and briefly began to state the reasons for his displeasure against the Russian government.
Judging by the moderately calm and friendly tone with which the French emperor spoke, Balashev was firmly convinced that he wanted peace and intended to enter into negotiations.
– Sir! L "Empereur, mon maitre, [Your Majesty! The Emperor, my lord,] - Balashev began a long-prepared speech, when Napoleon, having finished his speech, looked inquiringly at the Russian ambassador; but the look of the emperor's eyes fixed on him confused him. "You are embarrassed "Recover," Napoleon seemed to say, glancing at Balashev's uniform and sword with a barely perceptible smile. Balashev recovered and began to speak. He said that Emperor Alexander did not consider Kurakin's demand for passports to be a sufficient reason for the war, that Kurakin acted like that of his own arbitrariness and without the consent of the sovereign, that the emperor Alexander does not want war and that there are no relations with England.
“Not yet,” Napoleon put in, and, as if afraid to give in to his feelings, he frowned and slightly nodded his head, thus letting Balashev feel that he could continue.
Having said everything that he was ordered, Balashev said that Emperor Alexander wanted peace, but would not start negotiations except on the condition that ... Here Balashev hesitated: he remembered those words that Emperor Alexander did not write in a letter, but which he certainly ordered Saltykov to insert them into the rescript and which he ordered Balashev to hand over to Napoleon. Balashev remembered these words: “until not a single armed enemy remains on Russian soil,” but some kind of complex feeling held him back. He couldn't say those words even though he wanted to. He hesitated and said: on the condition that the French troops retreat beyond the Neman.
Napoleon noticed Balashev's embarrassment when uttering his last words; his face trembled, the left calf of his leg began to tremble measuredly. Without moving from his seat, he began to speak in a voice higher and more hasty than before. During the subsequent speech, Balashev, more than once lowering his eyes, involuntarily observed the trembling of the calf in Napoleon's left leg, which intensified the more he raised his voice.
“I wish peace no less than Emperor Alexander,” he began. “Haven't I been doing everything for eighteen months to get it? I've been waiting eighteen months for an explanation. But in order to start negotiations, what is required of me? he said, frowning and making an energetic questioning gesture with his small white and plump hand.
- The retreat of the troops for the Neman, sovereign, - said Balashev.
- For the Neman? repeated Napoleon. - So now you want to retreat behind the Neman - only for the Neman? repeated Napoleon, looking directly at Balashev.
Balashev bowed his head respectfully.
Instead of demanding four months ago to retreat from Numberania, now they demanded to retreat only beyond the Neman. Napoleon quickly turned and began to pace the room.
- You say that I am required to retreat beyond the Neman to start negotiations; but two months ago they demanded of me to retreat across the Oder and the Vistula in exactly the same way, and in spite of this, you agree to negotiate.
He silently walked from one corner of the room to the other and again stopped in front of Balashev. His face seemed to be petrified in its stern expression, and his left leg trembled even faster than before. Napoleon knew this trembling of his left calf. La vibration de mon mollet gauche est un grand signe chez moi, [The trembling of my left calf is a great sign,] he later said.
“Such proposals as to clear the Oder and the Vistula can be made to the Prince of Baden, and not to me,” Napoleon almost cried out quite unexpectedly for himself. - If you gave me Petersburg and Moscow, I would not accept these conditions. Are you saying I started a war? And who came to the army first? - Emperor Alexander, not me. And you offer me negotiations when I have spent millions, while you are in alliance with England and when your position is bad - you offer me negotiations! And what is the purpose of your alliance with England? What did she give you? he said hastily, obviously already directing his speech not in order to express the benefits of concluding peace and discuss its possibility, but only in order to prove both his rightness and his strength, and to prove the wrongness and mistakes of Alexander.

Today we will learn how to create and transfer static sites to a decentralized network, roughly speaking, the entire front-end of your site will be in a decentralized network, and the logic in the clouds.

1. Build Your Website Sources

Each site should have source codes, if you ordered your site from a company or a familiar programmer, ask for source codes. If you wrote the site yourself, then you are lucky, the source code is always there! In any case, you can always download them from an existing hosting. Create a "My First Decentralized Site" folder, put everything you need in it.

2. Transfer all possible logic to the cloud

If your portfolio site or landing page has comments, dynamic data (for example, a feed of posts), use comments through the Disqus platform. A feed of posts, if necessary, can be taken from Facebook, vk, twitter, medium, spark!

If you have a form where you save some data that is visible only to you - use cloud databases.

3. Check what you've edited

Open the folder where your brand new site is located, which is about to be uploaded to the decentralized network. Find the index.html file there (if it doesn't exist, create it and fill it in), also create a 404.html file whose content is appropriate.

Open index.html in the browser, if there are any problems, go to step 2, most likely you don't have all the logic transferred to the clouds.

Once you've tested everything, create zip archive, with your site.

4. Create a profile in a decentralized network

We go to DeNet Alpha, log in through Google or register ourselves.

By default, you will receive 50 tokens that can be spent on hosting your sites, soon you can earn them.

5. Uploading the site to the decentralized network

Click "Add site"
Fill in information about the site (Fig. 1)
Next, click on the pencil (Fig. 2)
Select "Download New Version"
We send our .zip archive
Profit

Fig 1

Fig 2

Enough for 3-4 months

Here is a note for the attentive:

Now the network is distributed, not decentralized
Registration is only for your convenience and the convenience of users.
Now tokens can only be spent on creating a website
Tokens can be earned
Tokens can be bought on the token sale.
Even we will not know what data you want to place with us

At the beginning of April, the rental application will be ready hard drive, follow us to get the privilege of being the first users and earn tokens.

Decentralized network Ricochet Internet from Lantern
Ricochet decentralized network: Internet from a lantern
Ricochet's wireless decentralized network has evolved since 1985
and existed in parallel with our usual ways of accessing the Internet.

In the world of technology, philosophical disputes ( Who is first? chicken or egg?) is not a place.
There is always a pioneer, a challenger, a challenger
opening up a new direction for others.

Now that 3G Internet can be set up by anyone
average cook, and dots WiFi access metropolitan areas have
literally on every corner, it seems incredible what else
fifteen years ago about data transmission over the air for the average consumer
and there was no question. In those days, there was no wired broadband Internet.
Good old dial-up, grinding sounds of modem protocols
and work in an uncomfortable position ( telephone socket in hotel
rooms according to Murphy's law was in the farthest corner of the room).

Marvelous, but it was at that time that she saw the light and, most importantly,
one of the most interesting wireless technologies has been actively developed
data transmission is a harbinger of the present wireless access to the network.
This technology has a name that sounds like a gunshot - Ricochet.

Past Ricochet

The Ricochet chain has a founding father. Yes, and what. Paul Baren
American engineer of Polish origin, one of the founders
packet-switched computer networks. Working for a government funded
company RAND Corporation, Baren in the late sixties comes to the idea
on the need to develop computer networks capable of
survivability to resist the very real nuclear threat at that time.

Data transmission systems then were based on the architecture
telephone networks of general purpose and had a centralized
(center - telephone exchange) or decentralized (many connected
centers - telephone exchanges) structure. It is obvious that even
such reliable way, like packet data, did not give one hundred percent
guarantees of packet delivery within a centralized or decentralized network infrastructure.

Paul Baren quite rightly called one
from the founding fathers of the internet. But his strong point has always been mesh networks.

Baren suggested alternative infrastructure that
he called distributed distributed). In a distributed network, each
of nodes is a potential router associated with one or more
network nodes. Thanks to such redundant connections, packets in a distributed network
can move along a set of dynamically generated alternative routes,
which allows the network to function even in conditions
failure of most of its nodes.

distributed network, functioning
according to these principles, has received the name "cellular (mesh) network".

Baren's proposed distributed (distributed)
network architecture is one of the classical network architectures.

Baren proposed mesh technology to the main customer
companies RAND Corporation- US Air Force. However, due to
company lobbying AT&T, which provided its telecommunications
channels for rent to the military, the project remained a project. True, the works of Baren
network developers are interested ARPANET. Larry Roberts, Internet Chief
in the laboratory DARPA, was impressed by Baren's fault-tolerant network model,
described in his article On Distributed Communications Networks",
and invited him to the project as an informal consultant.

Baren's involvement in the creation of the first options ARPANET led
to the common misconception that the Internet is purely military
roots associated with the need to develop a data transmission system,
so tenacious that it is able to easily withstand a nuclear attack by a potential
enemy and function in any critical conditions. By the way, the same great
and mighty skynet who captured April 19, 2011 in the film
"Terminator world domination, and there is a highly reliable military mesh network,
based on the Baren model.

In fact, ARPANET was purely a research project.
This network linked research centers, not military installations.
ARPANET puts data delivery efficiency first
between nodes in a reasonable time. Of course, Baren's work related to fault tolerance
networks have significantly influenced the routing methods in the modern Internet.
That is why Paul Baren along with Larry Roberts, Leonard Kleinrock
And Joseph Licklider considered one of the founders of the Internet.

Brief flash of fame:
Developing their ideas of distributed packet networks,
Paul Baren co-founded Metricom in 1985.
The purpose of its creation was to develop a data transmission network that does not have a clear
certain central switching node. This network was designed in the first
turn for the needs of the energy industry, which at that time tried to reduce the cost of the process
management of such extensive infrastructures as electric and gas networks.

Rent telephone channels from major US providers
cost a pretty penny, since computers communicating constantly
were in touch, which means they occupied the channel. That's when Baren's ideas came in handy.
to create a distributed network, the nodes of which independently carry out routing.
In order to completely abandon the lease of wired channels, such a network was decided
make wireless. As a protocol basis for Metricom
chose the growing radio ethernet standard.

During development, it became clear that such a network could become
competitive in the provider market. To the same thought
Investors also came, including one of the founders of Microsoft, Paul Allen.
Now Ricochet would be called a network last mile "because its main
task was wireless connection user to the Internet or corporate network.

By 1994, all the necessary
samples of equipment suitable for consumer purposes, and the company Metricom
officially entered the service market ISP with commercial network Ricochet.
Expansion of Ricochet began with the town of Cupertino - the very one where
the headquarters of Apple and the office of Metricom itself.
Total per year distributed network Ricochet stretched across the northern
the coast of San Francisco, and a couple of years later she entangled
New York, Los Angeles, Atlanta, Minneapolis, Dallas, Detroit and Miami.

Ricochet network coverage in 1995
any modern telecom operator can envy.

Key Components of the Ricochet Network - Wireless Modems,
who subscribers Ricochet received along with the contract. They connected
to a serial port (later to USB) and worked at a frequency of 900 MHz, providing
receiving and transmitting data at a speed of 28.8 kilobits per second
at a distance of one to five miles. They contacted the nearest microcellular
radio modem, called Poletop Radio.

Poletop Radio- microcellular modems that provide interaction
with many user modems and many similar devices.
They provide intelligent packet routing in the Ricochet network, forming
several alternative transmission routes. By sending the package
these nodes formed a signal ACK (recognition) sent to the previous
node in route. This signal confirmed the successful transmission of the packet.
Thus, each packet ricocheted back a confirmation of its delivery.
Hence the name of the entire network. Well, these nodes got the name Poletop because
that most often they were mounted on lampposts ( Streetlight Field)
- the most convenient place, of which there are a great many in any city.
That is why the network Ricochet most often grew along the streets.

All Poletop modems within a radius of ten to twenty miles contacted
with a wired access point - a special server, usually located
in one of the municipal buildings. This server provided high-speed
wired connection to the nearest regional IP network access interface.
Operating at a frequency of 2.4 GHz, Wired Access Point (WAP) provided high
(up to 128 kilobits per second) data exchange rate with multiple Poletop.
A little later, user modems began to work at the same frequency.

Most often, regional communication
the Ricochet network server was located in municipal buildings ( city hall).
Many regional IP network access interfaces
(NIF - Network Interface Facility) had leased communication channels to:
Internet providers that are partners of Metricom; corporate
subscriber networks Ricochet; control center ( NOC - Network Operations Center)
the most distributed network. The latter not only controlled
the state of all other network components, but also contained a name server Ricochet,
providing authorization of users connected to the network.

Working at Ricochet was not similar to any of the technologies
internet access available at the time. In fact, the user
turning on the laptop and the wireless Ricochet modem (it was self-powered),
could access the network anywhere in the city. His modem connected to the nearest Poletop,
which, communicating with neighboring Poletops, formed dynamic
packet traffic routes to the nearest WAP. More Ricochet packages
converted into IP packets and moved over leased wired networks.

In the late nineties, the Ricochet network had over forty thousand subscribers,
despite the high cost of modems (three hundred US dollars), paid (thirty dollars)
registration and a rather large (seventy-five dollars) monthly subscription fee.

All these costs are more than compensated by the opportunity to
access to the network anywhere - both within the hometown and on business trips
to other major cities. However, the Ricochet movement covered not only metropolitan areas.
The mass of towns of one-story America had the opportunity to create a small Ricochet structure.

Movement of user data packets
online Ricochet happened in the literal sense of the word from pillar to pillar.

In 1997 Paul Allen becomes the owner of the control
stake in Metricom. Analysts predict brilliant
the future of a promising and, most importantly, really working technology.
However, in 2001, having more than fifty subscribers
thousand people, company Metricom declares himself bankrupt.

Reason for bankruptcy? It's all about the wrong marketing policy,
chosen by management Metricom. Development Ricochet could not have affected
in the position of traditional ISPs, which quickly adjusted
their tariffs, making them truly popular. Moreover, understanding the potential
wireless access, most of them began to actively introduce Wi-Fi.
The operators did not doze cellular communication received in the face Ricochet organization example
wireless data exchange network on the existing infrastructure (lampposts, municipal premises).

At Metricom did not feel trouble and did not even think to do
equipment and rates are cheaper. Alas, the company was carried away by inflating
soap bubble - the troubles of all dot-coms. Funds were invested in "promising"
research to increase bandwidth networks, subscribers and shareholders
reported on the capture of new high-speed frontiers and the release of new modems.
forgot Metricom report only that the last couple of years before bankruptcy
she worked in debt, and this debt grew every day.

Ten years ago, the bubble burst. For a while the network continued
function, losing subscribers. For several years, its assets were bought up
various companies and organizations cherishing hopes to revive the former greatness
Metricom at least within a few individual cities. In 2004 the company
Terabeam has attempted to re-deploy the network in major cities. Trying bogged down
in bureaucratic correspondence with municipalities and endless
negotiations with regional providers. All this took place in the background
gaining GPRS access popularity and active development of public outlets WiFi.

On March 28, 2008, the Ricochet network officially ceased to exist.

Future of Ricochet

Good ideas don't sink into the abyss. And the Ricochet network is basically
had a great idea. Yes, now the average Internet consumer receives
Internet access without a modem Ricochet integrated into his smartphone,
mostly thanks to technology. 3G and WiFi. Such success
these technologies are not least due to the "death" of the Ricochet network.
However, why death? Ricochet like a well-known political figure,
lived, is alive and, I think, will live for a long time.

Judge for yourself. Based on experience Ricochet operates successfully
a lot of service data networks. For example,
fire protection systems and access control to protected objects.

If you need to deploy a network infrastructure
in places not equipped with traditional network access points
(for example, during rescue work in hard-to-reach places or when
man-made disasters), the ideas of the Ricochet network become indispensable.
There are even projects to deploy ricochet-like networks based on flying drone robots.

And further. Recently, there has been more and more talk about
that the near future of wireless network access is mesh infrastructure,
deployed on a multitude of user devices that any metropolis is simply flooded with.
So maybe Ricochet technology yet " ricochet"from the past to the future.

This study explains how the failure of one Autonomous System (AS) affects the global connectivity of a particular region, especially when it comes to the country's largest Internet Service Provider (ISP). The connectivity of the Internet at the network level is due to the interaction between autonomous systems. As the number of alternative routes between ASs increases, fault tolerance develops and the stability of the Internet in a given country increases. However, some paths become more important than others, and having as many alternative paths as possible ends up being the only way to ensure system reliability (in the AS sense).

The global connectivity of any AS, whether it is a minor ISP or an international giant with millions of service consumers, depends on the quantity and quality of its paths to Tier-1 providers. As a rule, Tier-1 means an international company offering a global IP transit service and connection to other Tier-1 operators. However, there is no obligation within this elite club to maintain such a relationship. Only the market can motivate such companies to unconditionally connect with each other, providing a high quality of service. Is this enough incentive? We will answer this question below in the section on IPv6 connectivity.

If an ISP loses even one of its own Tier-1 connections, it will most likely be unavailable in some parts of the world.

Measuring Internet Reliability

Imagine an AS is experiencing significant network degradation. We are looking for an answer to the following question: "What percentage of ASs in this region can lose connection with Tier-1 operators, thereby losing global availability"?

decentralized network- A network in which the control and data processing functions are distributed among several communication nodes. [L.M. Nevdyaev. Telecommunication technologies. English Russian dictionary directory. Edited by Yu.M. Gornostaev. Moscow, 2002] Topics ... ...

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