Par with par

The term par-with-par is the translation of the English Peer-to-Peer , which is often shortened P2P . One finds sometimes the translation “station-with-station” or by “equal-with-equal”. It should not be confused with the concept of point-to-point Liaison, indicated in English by the expression Point-to-Point or with the point-to-point Protocol, or PPP .

  • the term of system par-with-par makes it possible to name a unit made up of users (of number not inevitably definite, nor fixes, but rather in a general way), of the protocol which enables them to communicate (Gnutella, BitTorrent, EDGE, etc), and of the operation of the protocol between these machines;

  • the term of network par-with-par makes it possible to indicate the machines and their interconnection at a time given , with a definite number of machines/users.
The term of node makes it possible to indicate the software present on a machine, therefore often a user (but possibly several). The term of bond indicates a connection (often TCP) between two nodes. The term of object indicates what is divided in a system par-with-par:
  • computing power (XtremWeb, a little as SETI@home but where everyone can propose a calculation);
  • files (Gnutella and so much of others);
  • services (DNS);
  • etc
In a system par-with-par, the nodes exclusively do not play the parts of customer or of waiter but can provide the two functions in parallel. They are indeed simultaneously customers and waiters of the other nodes of the network, contrary to the systems of the type Client-serveur. They play also the part of router, while passing the messages of research even the data towards their (S) recipient (S).

Introduction

The systems par-with-par make it possible several computers to communicate via a network, of to share information simply --file S generally, but also of flows Multi-media continuous ( Streaming ), the Calculation distributed, telephony (like Skype), etc on Internet.

The par-with-par allowed a decentralization of the systems while making it possible all to play the part of customer and waiter (see Customer-server). In particular, the systems of file-sharing all the more make it possible to have objects available that they are popular, and thus retorted on nodes. That then makes it possible to decrease the load imposed on the nodes dividing the popular files, which thus facilitates the increase in the number of nodes of files in the network, too called passage on the scale

The use of a system par-with-par requires the use of a particular Logiciel. This software, which fills then at the same time the functions of customer and waiter , is sometimes called serve (of the contraction of “ serv or” and of “cli ent ” due to Gnutella), or more commonly but in a reducing way, “customer”. It is the origin there of even term (of English: peer ) that one finds in par-with-par: the communications and the exchanges are done between nodes which have the same responsibility in the system.

The model par-with-par goes much further that the applications from file-sharing. It indeed makes it possible to decentralize services and to place at the disposal of the resources in a network. Any user of a network par-with-par can then propose resources and obtain some on the network. The systems par-with-par thus make it possible to facilitate the division of information. They return also the more difficult censure or attacks legal or pirate. These assets make systems par-with-par of the tools of choice to decentralize services which must ensure high availability while allowing low costs of maintenance. Proposals are applicable to more or less long run not to use waiters more, inter alia for:

  • the DNS,
  • the provision of software (distributions linux like Mandriva, setting-with-day Microsoft, etc);
  • to diffuse contents multi-media (streaming),
  • messaging software in line (skype).

The most known application currently remains however the file-sharing by the means of software at the same time customer and waiter like eDonkey/follower (original protocol eDonkey), FastTrack (used by KaZaA), etc

However, the decentralized systems par-with-par cannot call upon a waiter to coordinate the interconnection of users and to ensure of the weak times the requests. This is why appeared systems par-with-par which impose a structure between the users, in order to guarantee weak times: they are the decentralized systems structured . These systems take as a starting point structures of graphs static to inter-connect the users, represented in form nodes. They thus could do without waiters to ensure a burden-sharing among the nodes in term:

  • of traffic of received control and envoy by each node, which amounts limiting the number of users to which is
connected each node;
  • of many requests transmitted to a node;
  • of responsibility for the access to the resources shared in the network.
Lastly, these systems often could use a routing close to that of the graph of which they were inspired, thus decreasing it number of messages of requests forwarding in the network.

The context in which the par-with-par appeared

The first system par-with-par appeared in June 1999: Napster allowed user S to divide musical files with format MP3, a list of the files available on the network being put with provision thanks to a waiter. Each one could thus seek then to recover files. Only the recovery of object was thus decentralized.

In March 2000 arrived Gnutella. First system completely decentralized par-with-par, it allowed in effect research and recovery of objects without requiring waiter. The Software first allowing sound use was also used for the file sharing (without being limited to the music files).

However, diffusion of these files being often subjected to payment of taxes (Royalty S in general), who were not paid with the systems par-with-par. Attempts of the companies of Production and of distribution to prohibit or destroy these systems par-with-par was the first engine evolution of these systems.

Preceding histories

The reproduction and the division of cultural products or informative except trade-circuits existed under various forms before the par-with-par:

Actors

Since several years, all Net surfer equipped with a connection with one Band-width sufficient can recover Médias since Internet. The Net surfers use generally the contents downloaded for their personal use (from where the reference attends with right to the Private copy , of which the definition Juridique is nevertheless rather restrictive), others download with business ends.

The principal production companies of the disc or of the cinema (also called majors , Anglo-Saxon term) and them distributers was not prepared with a so easy access to files and with the contents. The recovery of these files having become banal, these companies now pain to put forward theirs right. The downloaders of Royalty files under S call upon the too high price of products marketed (Music S or Film S) and of the too old channels of distribution.

Géographiquement, if the systems par-with-par are accessible everywhere where Internet is available, the user S come mainly from the Pays developed S. the networks have tendency to organize itself geographically, i.e. the inhabitants of each Pays gather to exchange files in their Language (for the Film S) or concerning their Artist S (for the Music) for example.

Downloaded media

A study of 2004 on the system par-with-par EDonkey2000 show that in term of number of exchanged files, the first Média is the Musique, by representing about half of the files available, while the Vidéo S represent roughly 15%. The format more diffused is MP3, others formats owners (WMA, RealMedia, etc) or free formats (Ogg, etc) being present.

In term of quantity of Given S exchanged, in fact the video files are found most important, representative two thirds of the accessible information, relegating the audio files to 15% of the place catch by the files in the network. The exchanged files can also be files, Logiciel S, Image S or of the Document S.

In a general way, a correlation exists between the appearance of the systems of division files par-with-par and appearance of new formats of numerical files.

Evolution

Centralized systems or beginnings of the par-with-par

Technical sides

The centralized systems are the first systems par-with-par to have been born, in June 1999, when Napster was created. It was followed other protocols of standard Mrs., as DirectConnect (which evolved/moved in DC++). The Napster system proposes the downloading files musical, but it is not yet formally par-with-par, since it rest on the use of a stable waiter for the comparison of the users. The creator of Napster for that was easily and quickly put in lawsuit by large distributers of music like Time Warner.

Napster is a system of file-sharing, where the divided objects, files, are managed by a waiter index. They are in fact 50 to 150 waiters index, a méta-waiter reorientating the new nodes towards one of these waiters. A waiter contains the titles of files lodged by the network, and addresses it nodes which place them at the disposal. The waiters can also play the part of critics: for example, in Napster, only the division was authorized of audio files of format mp3. The Napster protocol was not officially diffused, and them analyzes of the protocol are thus based on retro-engineering. These analyzes allowed the ceration of free customer-server software, like Lopster, Xnap or Teknap, but also of nonfree customer-server software like WinMX. Free waiters also were born like OpenNap and OpenNap-ng. These last waiters make it possible to choose the divided files, thus removing the limitation with the files mp3.

In Napster, when a node seeks an object, it sends to the waiter a request in the form of character string, to find all the files whose title contains this chain. The waiter answers then by a list of nodes lodging a file corresponding to this research. Research can be limited to the waiter to which the petitioning node or being is connect launched on all the waiters. The exchange of the file is carried out then directly between the par which lodges the file and the par which seeks it. The stage of the transfer of the file is thus the only diffrence with the model Client-serveur. The architecture of this type of system thus makes it possible to divide the same files on different nodes.

This type of systems does not allow a good balance of load, because the number of waiter follows the number with difficulty users, which makes difficult the acceptance of new users beyond a certain limit. In addition, this centralization created a weak link which returns these types of systems particularly sensitive to attacks of the type denial-of-service . That can go until making the system unusable. It is this centralization which provided a point of attack against Napster: it has is enough to aim at the few waiters (their propritaire in fact) to cause the end of this system, thanks to legal attacks. Protection against the censure and the defense of the anonymity of the users cannot be correctly assured by centralized systems since it is enough to control the waiter to censure the nodes or identifies them for to obtain all the relative informations with the network. However centralization makes it possible to ensure an exhaustiveness of the answers, i.e. if an answer exists, it will be found because the waiter knows all the network. It also makes it possible to ensure an authentification of divided files in a simple way. The existence of a waiter also makes it possible to circumvent the difficulty raised by avoid-fires, but the cost for the waiter is such qe this solution was abdandonnée in the majority of the systems centralized.

Sociological aspects

The increase in the flows, the fall of the prices continues offers of the suppliers of access, peripheral computers and (multi-media, engraving, Storage capacity in rise) is the technological factors and commercial which allows emergence in June 1999 of the first Logiciel used large scales: Napster. If it is with the departure created in another optics (its creator, Shawn Fanning, a young person student American 18 years, wished to easily be able to exchange Musique with his/her friends), it quickly becomes dedicated to the remote loading of media to the format MP3 on Internet in being pressed on a centralized search engine allowing the downloading files without passing by it waiter. As of first week: 15,000 people downloaded the software, then 23 in July 2000 million.

Facility of use of Napster (remote loading/sending/search for titles) and the fact that it that is to say not held specialists ensures him a fast success. Increase fulgurating in the number of user S causes such a considerable increase in the number of Chanson S available. Consequently, the illegal downloading forms integral part of phenomenon Internet and the software par-with-par become the news applications to the mode.

However the “temporal availability” is still low (many users still paid Connection Internet to the minute) the users do not leave their personal computer connected permanently, close Napster as soon as they surfent (the flow is still too weak to make it possible to use the two applications at the same time). The behavior of the users is thus defined by technological and financial factors. So with this moment, technically the remote loading of media is powerful in the Entreprise S and Université S, it are the hearths which are the Consommateur S and actors. There is shift between the technique and the use.

At that time one attends the emergence of a new behavior of the Internaute S which will reinforce remote loading: the illegal Trade of engraved CD (the engravers are available but the virgin media and engravers remain expensive) who by the attraction of the profit of the Vente causes a passion for the practice and pushes users more and more to use Napster and to be equipped.

Already under the blow of attacks of the '' majors '' of the music and of Artist S (Metallica and Dr. DRE inter alia), Napster is condemned not to allow more the file-swapping protected by rights through their waiters. For reasons Legal S, Napster is closed definitively in 2002.

Semi-decentralized systems: towards a dissemination of the waiters

Technical sides

Following the centralized systems systems created appeared to make the searchs for objects more effective. Indeed, if the hybrid systems make it possible to decentralize the search and the recovery for objects, they pain with to return results when the number of users increases. Indeed, in these systems, the method of research is based on a limited flood, i.e. a systematic sending research with all the users connected remotely lower than a fixed terminal. With the fur and measures that the number of nodes of the network increases, as well as the number of objects in the network, the flood limited proportionally less and less touches nodes of the network and thus less and less objects of the network. That decreases the probability of finding an answer. The solution consisting in increasing the terminal of the flood is not satisfactory because it increases the load of the network in an exponential way. However the philosophy of a system par-with-par rests a priori on an increase in the performances and effectiveness with fur and as the number of participating nodes, therefore that the number of objects, increases.

This is why system baseds on interconnections of stable waiters, like eDonkey in June 2000, or emulates in May 2002 (using the protocol eDonkey initially), were conceived to improve the results of a search. Each node not waiter, called sheet, is connected to a waiter. These waiters are stable, and manage a very great number of nodes (until a million nodes for follower for example). They do not need to communicate between them, and do not divide any file. The objects divided by a sheet are recorded on the waiter responsible for this sheet. When a sheet seeks an object, it sends its request to its waiter. This one then carries out research among the objects of the nodes which are connected to him. The role of the interconnection can vary according to the protocols. It does not have vocation to be used for to diffuse requests, but rather has a role of calculation of statistics, or maintenance list of the waiters under operation for example. This system loses in decentralization what it gains in smoothness and of many results. Indeed, centralization makes it possible to profit from finer research on waiters gathering a great number nodes thus of files. Several tens of waiters make it possible to ensure a continuity in the service.

eDonkey is a customer-server software allowing the file-sharing. It gave its name to the protocol which uses waiters connected to each other, so that each one knows which waiter is under operation. This protocol is also at the base of the customer-server software emulates (which proposed extensions to the protocol), eMule+, and MLDonkey. The nodes are connected to only one waiter (although nothing prohibits to be connected to several like proposed it MLDonkey). The nodes can carry out research on their waiter but also with the whole of the known waiters, in order to maximize their chances to find a file satisfactory. The distribution of the customer-server software at the origin of the protocol eDonkey ceased in September 2005 following legal attacks.

Each node is seen allotting a single identifier. If it is not connected through a fire wall, a node sees allotting an identifier depending directly on its physical address (addresses IP). When a node launches a request of research, it obtains answers containing each one of information on found file and the identifier of the node which lodges the data. If it wishes to download this data, it can is to calculate the physical address of the source starting from sound identifier, and that means that the source is accessible directly, that is to say the calculation of the physical address is impossible. In the second case, it is that the source is not accessible directly (that arrives when the port of the application TCP 4662) is not usable. That can be due to the fact that the source is connected to the system par-with-par via a fire wall, a proxy, one translation of address (NAT), or which it is occupied. The protocol then allows the sending of a request the waiter to which the source is connected so that it is connected itself with the applicant. The problem of a node behind a fire wall seeking to also communicate with another node him behind a fire wall persist and is not solved by this method. In any event, this functionality increases too much the load of the waiter and was decontaminated majority of waiters.

The multi-source remote loading is also allowed by eDonkey. The extension follower allows that, when a source is found, and if the file is in the course of recovery, the source which lodges the data provides the other sources which she knows in order to accelerate the recovery of data starting from several sources. In order to discourage the egoistic nodes, emulates set up an extension allowing a system of appropriations, using the algorithm of cryptography to public key RSA. This system allows the nodes which wait to download a file to advance more quickly in the queue of nodes suppliers to which it provided itself of the files, and thus to recover the file requested more quickly. It is thus about a local reward system . This system of credit is based on a identifier of user of 16 bits (different from the identifier of the node) who is generated by chance, and depend on the machine associated with the node. This identifier thus remains the same one during various connections of the node to the network.

eDonkey uses choppings of contents of files to differentiate them in a sure way. It independently breaks up the files into blocks récuprables, which makes it possible to accelerate the recupration of the files by paralleling the remote loadings. These blocks are identified by means of the function of chopping SHA1, which limits the probability of having a collision between two choppings. In particular, this function appears much more effective than the UUHash function used by FastTrack (system described further). Moreover, eDonkey identifies also each file in its intgrality by the concatenation of choppings (using function MD4). In the protocols eDonkey and emulates, it is not possible to allot more responsibilities to a node having capacities higher than the others. Moreover, two limits with the number of users exist:

  • a material limit prohibited all new connection when the maximum number of allowed users is reached.
  • a software limit prohibited all new arrival of node connected behind a fire wall (protected node) beyond this terminal.
Since 2004, certain waiters eDonkey censure the requests when they relate to certain key words (sex, xxx, etc), and prohibit the division of data when they are certain types (mp3, vidéos, etc). That once again points out one of the weakness of the centralized systems: sensitivity to the censure. However, in order to decrease one of the other problems arising from centralization and to limit the load of waiters, eDonkey integrated into its customer-server software the use of a table of chopping distributed baptized Overnet, and based on Kademlia. The customer-server software became on this occasion eDonkey2000. emulate also integrated this table of chopping distributed under the name of Kad! . Let us note that the administration of the network eDonkey2000 and the property of the customer-server software associated by the company MetaMachine put an end to the use of this protocol in September 2005, following legal attacks. The protocol emulates, depending on no company, continues however to function.

This type of systems rests on a certain centralization since it requires a certain number of waiters supporting all the load of the network. If a waiter is disconnected, all its users owe reconnecter with another waiter. The waiters, and thus the nodes which are connected there, thus present the disadvantage of being at the thank you of one attacks or of an overload. Because of centralization, certain waiters were launched in order to espionner the users. Indeed, several companies and associations specialized in the fight against the use systems par-with-par. Those can very easily identify the physical address of a user while being connected to a system semi-decentralized par-with-par. These organizations can even make function waiters in order to know what is divided by the users connected to these waiters. The identification of the nodes emulates being based on the physical address, it is possible of connatre the physical address of one node starting from its identifier. Since each result of a search for an object is accompanied by the identifiers of the sources, it is enough to carry out a research on an object to obtain physical addresses of users of systems par-with-par lodging this object. The semi-decentralized systems are thus not very suited to the protection of the users. Research is by defect nonexhaustive since it is not carried out on all the waiter. Whenever research is carried out on all the waiters, the answer will contain the addresses of nodes which were sent like answer it there more than one minute. Nevertheless, if centralization allows exhaustiveness, the nodes lodging of the popular objects receive many requests.

Sociological aspects

Thanks to the experiment Napster par-with-par, the programmers who use the systems par-with-par develop the technique fractionation of the files: hardly a Remote loading started, the recovered part is already available to the sending. A multitude of software give access to the same networks (Bearshare, WinMX, LimeWire, Shareaza). In the line of Napster, these Logiciel S offers to the Internaute S interfaces simple and usable by all.

Because of speed, technical projection and world extent of Internet, the work S are available as of their exit even before the exit with the Cinema, in Europe for example. Size of the files available increase (750, 800 Mo) with the reduction of the risks of failure of the remote loadings and the increase in the flows disponbiles.

Increase in the flows ADSL (128k at the beginning, 2048 kbit/s then 5 to 8 Mbit/s) as well as fractionation of the files reinforced competition between users of the network to recover the same file. Handling in order to maximize the ratio reception/sending becomes more frequent: modifications on Napster or blocking of the wearing of sending to mislead KaZaA or Follower. To leave its personal computer lit 24:00 /24 is not even useful any more to recover a file.

It is thus with better means, more a great choice of media, and an increased speed of remote loading that them Net surfers exchange files protected by Royalty. The trade unions gathering the '' majors '' disc and them '' majors '' of the cinema (RIAA and MPAA) become impotent attack directly the Net surfers then.

Initially, it is those which make a trade of media recovered by means of software of par-with-par which are aimed. Today, even of simple Net surfers “downloaders” are taken for target and are supposed to be useful examples in order to discourage this practice (more than 700 complaints have summers deposited through six European countries and: 5,700 impetuses in the United States since mid- 2003). Consequence direct in the hearths, certain sources affirm that the figures of illegal downloading would have dropped in little time: drop by 200 million music files available between 2003 and 2004.

: Dans the case of the France, this race with “very high banc” is allowed by one Economic situation of commercial, technical and political factors: the Deblocking.

The February 21st 2006, with 10:00, the waiter Razorback2, an indexer of contents of the system Ed2k was seized by the federal police force Belgian.

KaZaA time

As of 2001, while the first legal pressures weighed on Napster, being wary users on KaZaA Sharman Networks folded up, based on a architecture par-with-par decentralized (the Net surfers are connected directly between them and either via waiters centralized) thus more safe from the justice (the creator discharging from the activities of users). He is downloaded with more than 342 million specimens what is the record of the number of Remote loading S of a program for the time. He also confronted with justice, it can however continue its activity because it is the faulty behavior of the users which is condemned, KaZaA while not being responsible. Morpheus and Grokster, two similar software, is also judged kind (the security company of this last however was closed by decision of the courts American).

KaZaA, by filling the technical gaps and the Legal weakness of Napster, secures a success and a popularity quite as important while alluring the user S of this last. The new possibility to take again a Remote loading stopped and the fact of being able to download of several sources same a file in order to increase the speed (always coupled to an increase flows - beginnings of the cable in France…) allow to mitigate them disadvantages of the temporal availability. KaZaA knows an important expansion at the time of the exit with lower costs fixed prices unlimited (World Online, OneTel then first unlimited offer AOL in France in 2002, in the USA as of 1999).

This commercial factor causes the emergence of new behaviors on the networks par-with-par, the Internaute S let KaZaA function while they make another thing (surfing for example) then in the second time they leave their Personal computer connected permanently. There is thus an increase in the temporal availability but also quantitative of the Médias (it combines the facility of use of Napster and the clean diversity of the media up to now with ftp). In parallel, the flow of the connections Internet increases, by the cable then thanks to ADSL (technology is available as of 2000, the public offerings are in place the following year).

BitTorrent time

Despite everything, the changing is already ready for the traditional ones like KaZaA, and even for the recent ones clones of EDonkey. The generation of GrabIt and Bittorent cause to drop recently frequentation of their competitor. One sees also the appearance of systems par-with-par as ANts which functions on an anonymous mode. Concretely, the Donnée S travel of user to user in way completely quantified.

This report is reinforced by the last generation of Logiciel S represented by Bittorent, Overnet and GrabIt (that certain sources credit for 35% with the inbound traffic with files on the Net). They optimize to the maximum the band-width in sending and reception. They are not direct competitors of EMule because they do not propose not such an important diversity of sources. They do not misent on the temporal availability (the work S are accessible a few months to more) but on a maximum flow in continuous flow. This news applications is technologically more advanced (file-sharing thus cut out less heavy and faster with to download).

One almost witnesses an increase in the size of Médias available (several gigaoctets) because of flow continuous enters the pars of the network. The supports being able to store those also standardize themselves: the equipment of the hearths as readers engravers DVD, platinums DVD and DivX of living room increase. The par-with-par opens and instigates new markets: that of the Wandering mp3, the Car radio S Mp3 where one connects a Clé USB and finally walkmans Multi-media S with Windows media Center “embarked”.

The quantified generation

Technical sides

The laws and lawsuits appeared since the beginning of the years 2000 on the par-with-par and the Private copy accelerated the technical evolution of the systems par-with-par towards systems asserting a total anonymity of the users. One finds in this Alliance category, Share, WASTE, freenet, GNUnet, Transfers, Grouper, TribalWeb, etc For the moment these systems are used little by the followers of par-with-par.

In freenet, the oldest system but also most complete, anonymity is supposed initially assured being by decentralization of the system thus by that its coding, i.e. the use of cryptography for encoder information forwarding on the network. There is thus no connection on a waiter, and the requests pass by several nodes in order to make their tracing difficult. These nodes making forward information are other users of the network. Various quantified fragments of the same file thus pass by various machines, and are recopied there (mechanism of mask), before arriving at the final computer having required the remote loading. This mechanism of prohibited mask quantified even the reading of information by the owner of the machine which lodges it. Although total anonymity is technically impossible, the goal is to make very difficult (in term of time and money) to know the name, nature, the contents, and the people related to these data, including for the supplier of access to Internet itself, and thus to prevent any possibility of identification of mass.

Examples of anonymous protocols par-with-par asserting itself (November 2007):

Software only open-source in the order of popularity:

Here, only the software is presented allowing an external anonymity and between the users, because certain software such as AllPeers, Hamachi, Hybrid Share, OnShare, GigaTribe, Retroshare, does not allow anonymities between the users.

Sociological aspects

The software formerly attacked in justice is reconverted into the Vente legal of Music on Internet (Napster, KaZaA). But the Net surfers arrived to to pirate these versions in order to be able to continue with to download, on more legitimate systems a priori .

The most important recording companies showed them a long time Supplier of access to Internet to push with the use of the par-with-par because of their race to the flow and of publicities which praised the possibilities of remote loading of Musique and Vidéo S before even creation legal offers on the matter in order to attract the customers. With the wire of time, these companies have work, Procès after lawsuit to condemn this activity. Because of pressure exerted by those, one notices that none of system par-with-par perdure, excluded those based on open protocols.

Technical sides

The waiter S par-with-par function in the near total of the cases in synchronous mode: the transfer of information is limited to the elements connected at the same time with the network. They can use the protocol TCP like transport of the Donnée s (it lays down functions in Duplex, the reception of the data is thus confirmed and their integrity is assured). On the other hand, certain uses as the continuous one ( Streaming ) require the use of a protocol more light and more rapid, like UDP, although less reliable, even if it means to ensure themselves integrity of the transmitted data. UDP is also the protocol more used to transmit messages enters waiters in the partly centralized systems.

The systems par-with-par are divided into several main categories, according to their organization.

Structure centralized

Examples: Napster, Audiogalaxy, EDonkey2000

In this architecture, a customer (a Software used by the members) connects himself to a waiter which manages the divisions, research, the insertion of information, although those forward directly user with the other.

Some consider that such architectures are not par-with-par, because a central server intervenes in process. Others answer them that the transferred files do not pass by central server. It is the most fragile solution since the central server is essential to the network. Thus, if it is removed, following an action in justice for example, as it was the case with Napster and Audiogalaxy, all the network crumbles.

Structure decentralized

Such a architecture makes it possible to resist such attacks, since the Logiciel customer does not connect himself to single a waiter but to several. The system is thus more robust, but the search for information is more difficult. It can be carried out in decentralized systems not-structured, like Gnutella, where research requires a number of messages raised, proportional to the number users of the network (and exponential according to the depth of research). In the structured decentralized systems, an organization of connection is maintained between the nodes. The majority are based on the distributed Table of chopping S, making it possible to carry out research in a number messages growing in way logarithmic curve with the number of users of the network, like EDGE, Chord, freenet, GNUnet, Tapestry, Pastry and Symphony.

Another solution was considered, consistent in the use of “super-nodes”, elements network chosen according to their their band-width and computing power, fulfilling useful functions with the system, like the indexing of information and the role of intermediary in the requests. This solution, returning the system a little less robust (the targets “to be attacked” in the network so that the system becomes inoperative are fewer than in a system of the Gnutella type, for example), is employed in the systems FastTrack, like KaZaA. The nodes of the network can then become super-nodes and vice versa, according to the needs for the system or of their own choice.

In the same way, the system EDonkey2000 uses fixed, more vulnerable waiters because fewer and less flexible that the super-nodes FastTrack.

Legal aspects

The Logiciel S of Téléchargement par-with-par cause a sharp polemic at present. Indeed, according to the Royalty companies of , the systems par-with-par are used almost exclusively for the remote loading of copyrighted contents by royalties (copyright), i.e. with the Reproduction and division of cultural products without agreement of having rights.

Nevertheless the systems par-with-par are very much used to diffuse legal contents (under free license like for example the site Jamendo does it, or whose property right has expired), it is indeed very expensive to have infrastructures allowing the diffusion of files (services of extremely expensive lodging because requiring a band-width extremely high). That makes it possible for example to distribute legally distributions Linux by the means of these systems (generally BitTorrent) offering very important flows so much of world downloads the same file.

Moreover, one amendment with the law DADVSI, proposed by the deputy Alain Suguenot, was to legalize the par-with-par under certain conditions. That was to make it possible to widen the scope of application of the Private copy by creating a new tax optional on the subscription with a FAI to use a system of Global license framing the use of the systems par-with-par. But this amendment was not adopted. Law DADVSI was published on August 3rd, 2006 in the Official journal not modifying the principle only any reproduction or diffusion of files, via the software of peer to peer, without authorization of beneficiaries constitutes a counterfeit. Recently Court of Appeal of Paris, in a stop of April 27th 2007 and in another of May 15th 2007, as well as the TGI De Montauban on March 9th 2007, drew aside the exception for private copy and condemned the internautes.

A question remains outstanding: does the exception of Private copy suppose that the Fichier from which the copy is made is licit? The Court of appeal, in its stop of May 30th, 2006, had evoked this point while reproaching the Court of Appeal of Montpellier for having released a student shown to have illegally copied 509 Films without pronocer from the character sells by auction or not source. The business had been returned before the Court of Appeal of Aix-en-Provence. This one eluded this question by melting the judgment of the young Net surfer about the fact that it prétait litigious CD with his friends and thus exceeded the framework of the privé.
use

September 6th, 2007, the TGI of Saint-Brieuc cancelled the whole of the procedure and thus the continuations against a Net surfer suspected of having downloaded 149.000 files. To proceed to its report of counterfeit, the Civil society of the producers of gramophones should have had the authorization of Cnil to carry out a data processing personal on the infringements. December 14th, 2006, the TGI of Bobigny had cancelled a similar procedure.

Remote redistribution of public contents

Another question relates to the redistribution of contents televised (inter alia educational): on which basis of the legal copies by recording on line on Video tape recorder or Numériscope would cease they being it when they are off-line by Internet, while at the same time the spectator has already, as a taxpayer, paid for these contents? France 5 put an end to this problem while specifying at the head of several of its programs that those are entirely free rights for use in class.

Public access to the already free inheritance of rights

Another question relates to that of the Archives of INA, organization of State, concerning contents which were already paid, and whose diffusion by means of mass (DVD) is only seldom possible. One could plead that the public non-availability of these files on Internet represent a Abus right S on behalf of INA.

Fights against the par-with-par

To fight against the hacking, the majors of the disc and the cinema have several solutions at their disposal. The first consists in calling upon companies of statistics so that they place waiter S spies on the systems par-with-par like Follower. Software S connect automatically to all the waiters placed in their list, and thus to the waiters spies, to send their statistics of Remote loading and lists it files put in division. That makes it possible to pin Internaute S in red-handed for then assigning them in justice.

Another possibility, which turns over the system against the followers of the par-with-par, is to call upon others companies so that they manufacture and pollute the networks with false files (of the fakes), what can have like effect to discourage the downloaders and to resign them to turn to the platforms legal which proposes sure contents and of quality. However, it remains only little or more company specialized in this kind of existing actions because those went bankrupt.

Finally the fight against the illegal Téléchargement of file implies the constitution of an alternative offer of legal downloading and competing in term of abundance, price and of comfort of use. The offers of Vidéo to the request at the disposal of the consumers are densifient with catalogs of several thousands of titles. In music, the models of unlimited remote loading multiply.

In November 2007 the chairman of Fnac (France) Denis Olivennes proposes with the government Sarkozy to prohibit the illegal downloading by sanctioning the subscriber with the Internet by the assistance of the Fournisseur of access to Internet, however emails warning will be sent to the users in advance.

Limitations

If, today, majority of the problems due to the first protocols of par-with-par not optimized are solved, the principal limitations of the systems par-with-par are legal: they undergo in particular the pressures of the industry of the Musique, such RIAA, which fights against these systems making it possible to withdraw itself from Royalty S in all impunity.

Certain limitations also depend on the user S: it developed at some a bulimia of Donnée S, regarded as perishable, which are downloaded, then finally stored, filed, finally removed, without to be really exploited. Sometimes the Logiciel S of par-with-par are modified by their users, with an aim of maximizing it Remote loading of data while limiting to the maximum téléversement ( upload ) and killing, at the same time, the division. Nevertheless such practices are supposed being limited on certain systems thanks to a system of appropriations or of priorities between software thus eliminating these extreme behaviors.

Certain structures a contrario develop techniques of URL flipping and give for to receive and are based on the dynamics of the systems par-with-par in a more positive way.

Outlines

The history of the par-with-par undoubtedly makes only start. The architecture decentralized (see Table of chopping distributed) offers new prospects, by the stamping from the limits current of the band-width.

So today the par-with-par is especially used to exchange Film S, Musique S and Image S, it will allow soon to diffuse contents in real-time.

In the field of the diffusion Audio and Video (radio and tele by the Web), it is conceivable of to be able to diffuse contents without any cost for the diffuser. A televisual revolution is thus possible, with the appearance of small Television S and independent radios. That already exist in fact with the Logiciel PeerCast which makes it possible to diffuse its own radio.

Telephony is also aimed: software as Skype makes it possible to telephone free by Internet, and rests on a system par-with-par, which is likely to call into question current balance telephone operators.

The concept of perimeter geographical is abolished: one will be able to look at as well Japanese chains, as of to telephone Australian, by listening to an American radio, in the same way that one surfe on the Web today, independently of the national territories.

A complete redefinition of the current Media, industry of the leisures, and operators of telecommunications (recording companies, producing S of films/DVD, diffusers like the Fnac, France Telecom, television channels) is foreseeable.

Certain bunches go even until declaring this means of diffusion of the Culture as being one revolution comparable with the invention of the Printing works.

Beyond even of the diffusion of the data, the par-with-par in addition influenced many initiatives based on the same model of distributions of the sources, in very diverse fields.

Conferences and Workshops

Here a nonexhaustive list of the international conferences and workshops concerning the par-with-par:

Conferences

  • The IEEE International Conference one Peer-to-Peer Computing
  • " Peer-to-Peer Paradigm" Minitrack in Americas Conference one Information Systems

Workshops

  • International Workshop one Peer-to-Peer Systems
  • International The Workshop one Hot Topics in Peer-to-Peer Systems
  • International Fifth Workshop one Agents and Peer-to-Peer Computing
  • International Total Workshop one and Peer-to-Peer Computing
  • International Workshop one Peer-to-Peer Knowledge Management

Associated systems par-with-par and customer-server software

BitTorrent

ABC ~ Azureus ~ BitComet ~ BitTornado (Shadow' S Experimental) ~ BitTorrent '' Générique '' ~ BT++ ~ Flood ~ EXeem ~ KTorrent ~ MlDonkey ~ Opera ~ The Pirates Bay ~ PTC ~ qBittorrent ~ Shareaza ~ TorrentStorm ~ Transmission ~ µTorrent ~ WinMobile Torrent ~ Xtorrent ~ Transmission

Gnutella

Limewire and its clone, Frostwire ~ Shareaza ~ Acquisition (Mac) ~ BearShare ~ Cabos (Mac: Aquisition + Limewire) ~ Gnucleus ~ MlDonkey ~ Morpheus ~ mlmac ~ Poisoned ~ PeerCast ~ Phex ~ Swapper ~ XoloX ~ Mutella ~ IMesh

Napster

OpenNap ~ mlmac ~ Poisoned ~ lopster

FastTrack

Kazaa ~ Grokster stopped by MPAA and RIAA ~ IMesh ~ GIFT ~ Mlmac ~ Poisoned

EDonkey2000

EDonkey2000 (regrouping eDonkey2000 - Overnet) ~ MlDonkey ~ Follower ~ XMule ~ AMule ~ Shareaza ~ LMule

MP2P

Ice axe ~ Blubster ~ RockItNet

freenet

Frost - the software which makes it possible to use the forums of freenet. ~ Fuqid - to publish Web sites. ~ Freemail

GNUnet

GNUnet ~ Espra (is not developed any more, cf Frost)

Direct Connect

Direct Connect ~ DC++ ~ Zion++ ~ BlackDC ~ oDC ~ rmDC ~ cd. Pro

Ares Galaxy

~ Ares (Galaxy or Lite) ~ FileCroc

Other quantified systems par-with-par and/or partially anonymities

Transfers - File sharing only. ~ Nodezilla - Multi functions. ~ Spider ~ Tor (network) - Great project resulting from the EFF. Navigation Web, etc ~ Winny (stopped) - File sharing only. With given rise to Share.

Other systems

AllPeers ~ Alpine ~ ANts P2P ~ bwa ~ EDGE ~ Carracho ~ Chord ~ Dexter ~ Evernet ~ Filetopia ~ FreePastry ~ GPU ~ Groove ~ Hotwire ~ JXTA ~ JXMobile ~ KoffeePhoto ~ Kademlia ~ LimeWire ~ MojoNation ~ OFFsystem ~ P2PS ~ Pastry ~ PixVillage ~ Rshare ~ Scribe ~ Soulseek ~ Swarmcast ~ Symphony ~ Tapestry ~ TribalWeb ~ Wambo ~ WinMX

See too

Search engine

Internal bonds

External bonds

Sites general practitioners

  • ''' Open-Files.com ''' the independent topicality par-with-par: emulate, eDonkey, Overnet, BitTorrent, Ares, Gnutella…

  • ''' Ratiatum ''' (French-speaking Gate on the par-with-par)
  • Étude and use of technologies par-with-par
  • ''' P2PFR.com ''' (1 {{French-speaking er}} Portail on the par-with-par) Restons simple, let us go right to the goal
  • ''' P2PMag ''' (the first French-speaking magazine dedicated to the par-with-par exchanges)
  • Terminologie (Québécois Office of the French language)
  • ''' Audionautes ''' (Defense association of the audionautes, users of the par-with-par)

References

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