Torrent

CHAPTER III PROBLEM ANALYSIS

What is Torrent? Torrent is a method for file sharing (commonly called download) via internet using a new peerto-peer protocol called .torrent that’s usually used to distribute large amounts of data. Torrent protocol is different than ordinary conventional transfer method. The conventional downloads commonly using the HTTP or FTP protocol which needs a server for placed the data. A torrent protocol not always using the server, a torrent can download data both from server and client. So it’s possible to download data from client when the server is down. The main distributor of the complete file or collection acts as the first seed which called seeder. Each peer who downloads the data also uploads them to other peers.

The history of Torrent Programmer Bram Cohen designed the protocol in April 2001 and released a first implementation on 2 July 2001. It is now maintained by Cohen's company Torrent, Inc. Usage of the protocol accounts for significant Internet traffic, though the precise amount has proven difficult to measure. There are numerous Torrent clients available for a variety of computing platforms.

File transfer process A Torrent client is any program that implements the Torrent protocol. Each client is capable of preparing, requesting, and transmitting any type of computer file over a network, using the protocol. So the torrent process is always depending with torrent client itself. There’s come torrent technical term, such as:

•

Seed: is a side that provides complete parts of file. More seeder you have, you get more speed. In example if there 10 torrent client act as seeder, so that’s mean there’s 10 complete file were distributed/shared.

•

Peer: Peer providing the initial copy is called the initial seeder, which doesn’t have a complete file. A peers currently transferring pieces of the files specified in the torrent.

•

Ratio: is comparison between the uploader and downloader. Torrent ratio is a number calculated by dividing the amount of data that user has uploaded by the amount of data they have downloaded. Ratio over means that user sent more data then received.

•

Leecher: is a peer that’s not share its data. The leecher downloads the data, but he doesn’t upload it in the same time. The leecher is a client who has a bad ratio.

•

Swarm: Swarm is overall side who joined the transfer process.

•

Torrent Client: is any program that implements the Torrent protocol. Each client is capable of preparing, requesting, and transmitting any type of computer file over a network, using the protocol. Example of torrent application such as BitTorent, µTorrent, BitComet, KTorrent, Opera Browser, and Deluge.

Data Distribution Method The torrent file (with extension .torrent) is not currently a file, it acts as an address or carrier to the main file. The .torrent address will guide to the torrent server or client who has a file that’s requested. Torrent makes many small data requests over different TCP sockets, while webbrowsers typically make a single HTTP request. The torrent protocol is different with ordinary protocol like FTP, in FTP the download process is using a server as the main place of data. And also it can only download a single file from a single server. In example, with FTP we can’t download a folder (not a file) from multiple servers. The torrent protocol can download both from multiple servers and multiple clients. So the torrent doesn’t depending with a server to download the file, it can also download from client who has

the requested file. This condition is useful while the servers are down. And also it can download multiple file or folder. Data Distribution Illustration

In this picture, the colored bars beneath all of the clients represent individual pieces of the file. After the initial pieces transfer from the seed, the pieces are individually transferred from client to client. The original seeder only needs to send out one copy of the file for all the clients to receive a copy. Relative to standard internet hosting, this provides a significant reduction in the original distributor's hardware and bandwidth resource costs. It also provides redundancy against system problems and reduces dependence on the original distributor.

How to create a torrent file Creating a torrent is very easy, and sharing in Torrent is more involved than with other p2p applications. This is the result of the protocol that makes this distribution system so efficient. Torrent shares content by breaking it up in small pieces and distributing them randomly between peers. Those peers then share these pieces with each other. This saves the seed the trouble of sending the same pieces over and over to different peers and enables all the peers in a swarm to participate to the distribution of the files regardless of their percentage of completion. Before you make a torrent, it would be wise to pick a site and review its policies and rules. Your site of choice may have restrictions about content; some do not allow porn, some specialize in specific type of content (such as music, or anime). And do not share an illegal content or content protected by copyright. 1. Open Torrent 2. Select File -> Create New Torrent, or alternatively select the Create New Torrent button 3. To select a single file, select Add File. To select a folder containing files and folders, select Add Directory. 4. Select the files or folders you wish to upload and press OK. 5. In the Trackers box, add the address, in example: http://tracker.boxtorrents.com:2710/announce.php 6. Place a checkmark in the box that says Private torrent. 1 7. Select Create and Save as..., the .torrent file will be created. 8. Select the destination you wish your file to be created in and click Save. 9. You are done. You are now ready to offer to the tracker. The torrent file you’ve made is available only when you’re online, if you’re offline, then your torrent will be not available. The tracker maintains lists of the clients currently participating in

the torrent. Alternatively, in a trackerless system (decentralized tracking) every peer acts as a tracker. This is implemented by the Torrent, µTorrent, BitComet, and KTorrent.

Downloading torrents and sharing files Users browse the web to find a torrent of interest, download it, and open it with a Torrent client. The client connects to the tracker specified in the torrent file, from which it receives a list of peers currently transferring pieces of the file specified in the torrent. The client connects to those peers to obtain the various pieces. Such a group of peers connected to each other to share a torrent is called a swarm. If the swarm contains only the initial seeder, the client connects directly to it and begins to request pieces. As peers enter the swarm, they begin to trade pieces with one another, instead of downloading directly from the seeder. Clients incorporate mechanisms to optimize their download and upload rates; for example they download pieces in a random order to increase the opportunity to exchange data, which is only possible if two peers have different pieces of the file. The effectiveness of this data exchange depends largely on the policies that clients use to determine to whom to send data. Clients may prefer to send data to peers who send data back to them (a tit for tat scheme), which encourages fair trading. But strict policies often result in suboptimal situations, such as when newly joined peers are unable to receive any data because they don't have any pieces yet to trade themselves or when two peers with a good connection between them do not exchange data simply because neither of them wants to take the initiative. The client reserves a portion of its available bandwidth for sending pieces to random peers (not necessarily known-good partners, so called preferred peers), in hopes of discovering even better partners and to ensure that newcomers get a chance to join the swarm.

Indexing The Torrent protocol provides no way to index torrent files. As a result, a comparatively small number of websites have hosted the large majority of torrents linking to the file. Several types of websites support the discovery and distribution of data on the Torrent network. Public tracker sites such as The Pirate Bay allow users to search in and download from their collection of .torrent files; they also run Torrent trackers for those files. Users can typically also upload .torrent files for content they wish to distribute. Private tracker sites such as Demonoid operate like public ones except that they restrict access to registered users and keep track of the amount of data each user uploads and downloads, in an attempt to reduce leeching. There are specialized tracker sites such as FlixFlux for films, MVgroup for educational content, fullcaliber.be for metal music, PureTnA for pornographic content, and TV torrents for television series. Often these will also be private. Search engines allow the discovery of .torrent files that are hosted and tracked on other sites; examples include Mininova, Monova, BTJunkie, Torrentz and isoHunt. These sites allow the user to ask for content meeting specific criteria (such as containing a given word or phrase) and retrieve a list of links to .torrent files matching those criteria. This list is often sorted with respect to relevance or number of seeders. Bram Cohen launched a Torrent search engine on http://search.Torrent .com that commingles licensed content with search results. Metasearch engines allow searching several Torrent indices and searching engines at once.

Multitracker Another unofficial feature is an extension to the Torrent metadata format proposed by John Hoffman and implemented by several indexing websites. It allows the use of multiple trackers per file, so if one tracker fails, others can continue supporting file transfer. It is implemented in several clients, such as Vuze (former Azureus), BitComet, BitTornado, KTorrent and µTorrent. Trackers are placed in groups, or tiers, with a tracker randomly chosen from the top tier and tried, moving to the next tier if all the trackers in the top tier fail. Torrents with multiple trackers can decrease the time it takes to download a file, but also has a few consequences: •

Users have to contact more trackers, leading to more overhead-traffic.

•

Torrents from closed trackers suddenly become downloadable by non-members, as they can connect to a seed via an open tracker.

Legal issues There has been much controversy over the use of BitTorrent trackers. BitTorrent metafiles themselves do not store copyrighted data, hence BitTorrent itself is not illegal—it is the use of it to copy copyrighted material that contravenes laws in some locations. Various jurisdictions have pursued legal action against websites that host BitTorrent trackers. High-profile examples include the closing of Suprnova.org, Torrentspy, LokiTorrent, Demonoid (now back online), OiNK.cd and EliteTorrents.org. The Pirate Bay torrent website, formed by a Swedish anti-copyright group, is noted for the "legal" section of its website in which letters and replies on the subject of alleged copyright infringements are publicly displayed. On 31 May 2006, The Pirate Bay's servers in Sweden were raided by Swedish police on allegations by the MPAA of copyright infringement; however, the tracker was up and running again three days later.

Torrent Websites The Torrent tracker is a website. There’s a lots of Torrent trackers on the internet, and almost all website using the same method. The most popular Torrent Website is The Pirate Bay (http://thepiratebay.com), isoHunt (http://isohunt.com), and Demonoid (http://www.demonoid.com).

•

The Pirate Bay: The Pirate Bay (often abbreviated TPB) is a Swedish website that serves as an index for torrent files that it tracks. It bills itself as "the world's largest BitTorrent tracker" and is ranked 91 (as of 16 July 2008) in the Alexa ranking list. Initially established in November. According to the Los Angeles Times The Pirate Bay is "one of the world's largest facilitators of illegal downloading", and "the most visible member of a burgeoning international anticopyright or pro-piracy movement.

•

isoHunt: isoHunt is a BitTorrent index with over 1,100,00 torrents in its database and 16 million peers from indexed torrents. With 7.4 million unique visitors as of May 2006, isoHunt is one of the most popular BitTorrent search engines. Thousands of torrents are added to it each day as well as deleted for a multitude of reasons. On average, isoHunt users perform over 40 million unique searches per month.

•

Demonoid: Demonoid is a website and Torrent tracker that was originated by an anonymous Serbian known only by the pseudonym Deimos. The website indexes torrents uploaded by its members. It was the second largestand is the most popular private tracker for over a year, the 403rd most popularly ranked website in July 2007 according to Alexa, and had an estimated 3 million peers in September 2007. The site went off-line on November 9, 2007 due to alleged legal threats from the Canadian Recording Industry Association. On April 11, 2008 the site was brought back on-line. A news announcement was posted on the homepage

announcing that site had a new administrator due to the departure of Deimos, who reportedly left the position for personal reasons.

CHAPTER IV SUMMARY

Conclusion The Torrent protocol is the most efficient data sharing process. Because it’s easy, low cost, and not server-dependent. Relative to standard internet hosting, this provides a significant reduction in the original distributor's hardware and bandwidth resource costs. It also provides redundancy against system problems and reduces dependence on the original distributor. Torrent also allows clients to share their file, which in this case client act as a server. So the Torrent protocol allows multiple resource, and multiple file download (in example people with FTP can only download a single file, while with torrent people can download multiple files). It can be useful because with more file resource that’s published, means more speed to download. It’s different with conventional FTP, when download process is always depended with server, and it doesn’t support multiple file download, and multiple resource.

Suggestion There has been much controversy over the use of BitTorrent trackers. BitTorrent metafiles themselves do not store copyrighted data, hence BitTorrent itself is not illegal—it is the use of it to copy copyrighted material that contravenes laws in some locations. That’s situation allows people to share the file protected with copyright or illegal content freely. The torrent process makes people can download or upload illegal files without limitation and without law protec. So before you make a torrent, it would be wise to pick a site and review its policies and rules. Your site of choice may have restrictions about content; some do not allow porn, some specialize in specific type of content (such as music, or anime). And do not share an illegal content or content protected by copyright.