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[P2P] BitTorrent - Naslednja generacija P2P

[P2P] BitTorrent - Naslednja generacija P2P

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Tr0n ::

[Kaj je BitTorrent]

BitTorrent je ime protokola in ime peer-to-peer (P2P) programa za distribucijo datotek avtorja Brama Cohena. Z njim je možno množično prenašati datoteke pri visokih hitrostih brez velike obremenitve izvirnega strežnika in njegove povezave v svet.

Originalni BitTorrent odjemalec je bil spisan v programskem jeziku
Pyton, njegova izvorna koda je na voljo pod BitTorrent Open Source Licence

[Kako deluje?]

Če hočemo deliti datoteko preko BitTorrenta moramo ustvariti .torrent datoteko. .torrent je majhna datoteka ki vsebuje
  • Ime datoteke, velikost in hash vsakega segmenta datoteke

  • Naslov trackerja (beri spodaj)

  • Raznovrstna navodila za odjemalca(clienta)


Izvirni uporabnik nato postane "Seeder", BitTorrent protokol potem razbije datoteko/ke v manjše delčke ali segmente, ki ponavadi merijo okoli 256KB, ostali uporabniki ali "Peeri" potem prenašajo manjkajoče fragmente k sebi (prvotno od seeda) in uploadajo tiste, ki jih že imajo ostalim, ki ta fragment zahtevajo. Protokol je dovolj sofisticiran, da izbira uporabnike z najhitrejšo povezavo za distribucijo najredkejših fragmentov in se s tem izogne ozkemu grlu.

Glavni ključ pri usmerjanju je t.i. tracker. Gre za strežniški program, ki shranjuje informacije o datotekah, downloaderjih (leechers/peers), uploaderjih (seeders) in kontrolnih informacijah (hash,...).

Tracker prejme informacije o novem downloaderju(peeru) in pošlje nazaj naključne liste drugih peerov, vse potekao preko HTTP/HTTPS in TCP protokola. Peeri na določeno obdobje preverjajo/pošiljajo svoje stanje na tracker in med tem seveda up/downloadajo med seboj. Izvor datoteke (glavni seeder), ki ima celotno datoteko in jo ponuja drugim seveda ne download-a, ampak samo upload-a.Ob končanem prenosu datoteke postane tudi peer seeder in pomaga pri nadalnji distribuciji datoteke.

Pri BitTorrentu ni čakalnih vrst/queue-ov/rankov,... kot pri Overnet protokolu (E-mule). Downloaderji in seederji med seboj "razpršijo" dele datotek po naključju oz. stanju drugega userja. Upload drugih peerov se vedno spreminja in tako vsak pride na vrsto.

Povezava med uporabniki ima lahko dvoje glavnh stanj: choked/unchoked (zabasan/zaseden/prost) in interested/not interested (zainteresiran|nezainteresiran). Do prenosa pride takrat, ko ena stran ni chocked in je druga zainteresirana. Stanja o interesu se vedno prenavlja in je zelo pomembno, pove namreč, kateri client lahko začne kot naslednji downloadat takoj, ko ne bo več chocked (se pravi, da nima nobenega dela datoteke, ki jo drugi zahtevajo oz. je kako drugače zaseden).

[Odjemalci - Clienti]


[Povezave]
Več o BitTorrent protokolu


---------------------
Predlogi in pripombe na ZS --OmegaBlue
  • spremenil: bluefish ()

Gandalfar ::

Razmisljal sem, ce bi postavil kaksen lokalen tracker za 'bolj popularne datoteke' :)

A gremo zgradit en tak mini BT slovenski community? :)

Tr0n ::

Zakaj pa ne :). Sam tracker ne ustvarja veliko prometa, ker gre zgolj za simple tekstovno izmenjavo podatkov.

blabla ::

Kje je suprnova? :'(

Vse strani so pocrkale in strani z linki do strani so pocrkale. ADSL pa samuje.:|

Tr0n ::

Saj so se druge :).

tigrr ::

iz modune searcher-ja v razmislek:

2003/05/28 00:06:00
Well, it looks like almost all of the major torrent sites are down at the moment (so I don't feel quite so bad for the search engine still being down ... because it would only search about 1000 torrents anyways).

It's starting to look like the only way that bit torrents are going to survive will be to start distributing lots of files across many (ideally 200-1000+) functioning servers/trackers, making it much more difficult for massive sectors of the BT system to go down at once. This would require someone making it very easy for anyone to start their own tracker, and easy for people to post to these trackers. Then every site would have 10 or so torrents hosted, and every torrent could be duplicated a few times, and the majority of the torrents would be available the majority of the time.

Such a widespread system will take a while to develop, but it seems like the only viable solution for the BT problem. Having a few large sites simply will not work, because they will either become overloaded or shut down.

What needs to happen?
1. Creating and hosting a tracker needs to be made extremely simple. (This could be accomplished with a very good Step-by-Step guide, FAQ, and perhaps some utilities to help newbies)
2. Postings of new torrents would need to be distributed among the many trackers (This would necessitate communication between the trackers/servers in order to keep record of all of the existing trackers.)
3. Some means of searching through all the small sites would be necessary (Again, there would need to be communication between sites to keep track of what files were on which sites)
4. A generalized site protocol would need to be devised so as to keep things consistent across many sites (meaning that all sites would be similar enough that users would not have trouble navigating them)

Keep in mind that I am no authority on bit torrents, and am just rambling about things that I don't really understand (and you're reading it ;] ) In any case, the current Bit Torrent network paradigms need to be rethought... otherwise there are going to be more problems :[

Zgodovina sprememb…

  • spremenil: tigrr ()

Tr0n ::

Ne vem. Ni mi prevec vsec ideja o iskanju. Centraliziran tracker/torrent sistem bi verjetno pomagal, search pa bi ustvarjal samo se vec prometa, kar pa ni dobro.

Finta BTja ni v arhiviranju starih datotek, ampak predvsem o sheranju novih, priljubljenih, ki so dostopne samo kak teden ali vec, ce je datoteka zelo priljubljena. Neke vrste usernet newsgroup nacin.

Gandalfar ::

Se strinjam .. dosti mamo ze taksnih omrezij , ki to pocnejo na "drugacen" nacin.. ed2k in gnutella recimo.

BT se zdi odlicna stvar za downloadanje zelo popularnih stvari.

Me zanima koliko je kriticna masa, da to uspe... ene 15adsl userjev .. bi bilo dovolj za en zaprt torrent network?

Tr0n ::

CIm vec, tem boljse.

Pomembno je pac to, da ko user konca download, da pusti prizgan svoj upload, tako da datoteko dobijo vsi. Hkrati razbremeni upload ostalih seederjev in omogoca hitrejsi prenos. Ko datoteko dobijo vsi, se seedanje konca. Pri manjsih, zaprtih skupinah to ni tak problem.

Tr0n ::

No, avtor BTja mi je zaupal, da je zadeva optimizirana oz. deluje najbolje pri 20 do 40 userjih.

Binji ::

Hmm ko zazenem javi napako v parametrih. In tudi ce jih nastavim hoce se neki fajl. Kaj delam narobe?8-O
Kdor ne navija ni Slovenc, hej, hej, hej!

Tr0n ::

Najprej rabis .torrent fajl od datoteke, ki jo zelis downloadat. Dobis jih na raznih BT community straneh. Ko si to .torrent datoteko presnames na disk (ponavadi ni vecja od 50 kb) lahko najprej s TorrentSpyjem preveris, koliko seederjev/peersov ima. Za uspesen download mora imeti vsaj enega seederja, torej 1 complete file.

Nato pa enostavno 2x kliknes na .torrent datoteko in zazene se ti BitTorrent. Vprasa te po direktoriju. kamor zelis zadevo posnet in download se pricne.

Lahko se tudi zgodi, da je tracker down (tracket timeout). Potem ti ne preostane nic drugega, kot da datoteko poisces na drugi strani, kjer uporabljajo drug tracker, ali pa pocakas, da se tracker vrne.

Tr0n ::

Tr0n ::

Heh, preprosta in dobra razlaga BitTorrent sharing protocola. Bom kr pastal zadevico.

The problem with most P2P networks is that many people just don't like to share. They open up their program, download their files, then close the program before they can help anyone else. It's called leeching. Behavioral judgements aside, if everyone did this then nothing would ever get shared! To combat this, BitTorrent has gone back to the way of sharing you were probably taught as a young child: trading. Instead of waiting for the complete file to download before it starts to share, BitTorrent downloads the file in small pieces and shares each piece as it finishes. This makes it easier to get the file from many different people at once, thereby increasing the probably that you'll get a good download speed. It also means that downloading a file is more reliable than in some other networks. If Charlie has half of a file and Bob has the other half, Alice can get each half and put them together to get the whole file. Spiff, eh?

But this piecewise downloading doesn't necessarily combat the leech problem. As a backup plan, BitTorrent built in the other half of trading you probably learned as a kid: tit-for-tat. That is, if you give me one piece, I'll give you one piece back. BitTorrent will give you a few pieces of the file for free to help you get started, but after that you need to start giving some pieces back if you want to keep downloading. If you don't share, eventually everyone else will stop talking to you. Just like when you were a kid with your toys on the playground. In fact, BitTorrent goes one step futher and actually starts to favor the people who share the most. This means that the more you upload, the faster you'll download.

For example, Alice gets a few pieces of a file from Bob for free. She can then give those pieces to Charlie, if he doesn't already have them, which will motivate Charlie to return the favor and give her a bunch of pieces that she doesn't have. She then goes back to Bob with those pieces, and the cycle continues and grows. Why don't Bob and Charlie talk directly? Maybe they do but they haven't gotten to those pieces yet. Or maybe their systems aren't configured right and they can't talk directly to each other.

How does all this start? With BitTorrent, it starts with a tracker. Like the name suggests, a tracker keeps track of people who are interested in torrents. When you download a .torrent file it contains a link to a tracker as well as an identifier (hash) which is unique to that specific torrent. Your BitTorrent client then connects to the tracker and asks for a list of all people interested in that torrent. At the same time, the tracker adds you to that list so that other people know that you are interested. Your BitTorrent client will also periodically asks the tracker for an updated list. That's all a tracker does: keep track of that list for each torrent, and give it out to people who are interested. The tracker does not know anything else about the torrent, nor does it send you the file. It just shows you where to go to get the file. (Like an Information Booth at a mall.)

kilergas ::

Odkar je sla supernova rakom zvizgat ne najdem en klinc nic;((
A je se kaksen site kot supernova?Prosil bi za kaksen link,..

frenk ::

kilergas:hm...kašna je pa bla supernova??...al mogoče taka kot sharereactor ali filenexus:\

sloncek ::

Suprnova bo nazaj pršla v parih dneh. Zdej se piše PHP skripta in bo končana v 2-3 dneh. Pol bo pa suprnova pršla nazaj še bolša kot prej.
Mal potrpljenja fantje :) .

Klemenn ::

Preglejte tole oz tole.

aja, ka bi bil en velik problem, če bi recimo naredili slovensko stran ka0 supernova;

se da iz tega potegnt ven ``linke´´ (kot pri emuli recimo), polj pa en eno skripto naredi, pa lahk vsak posameznik to uploada (sm listo)? :\

Tr0n ::

sloncek: k33p up the great work! :)

Uporabo BT++ klienta odsvetujem, ker ni namenjen share-anju ampak bolj leechanju in ima se kar precej bugov.

Najboljsi je trenutni BitTorrent EXPERIMENTAL.

Gandalfar ::

Jebediah: sej suprnova je slovenska stran :>

Klemenn ::

ja0. nisem vedu ;)

sm mal čudno se mi je pa zdelo, k je blo gor Sloncek napisano ;)

bt++ je isti kot navaden bt sm da ma naprednejši GUI, drgač pa kdor hoče leechat bo že vedu kako :\

Wolverine ::

Ze dolgo uporabljam to zadevo. Uporabljam predvsem za anime. Edina negativna lastnost je, da ti zafila upload, zato dam vleci preden grem spat, ker je drugac surfanje zelo pocasno. BitTorrent XERIMENTAL je zelo ok zadeva, samo bodo spet vsi dajali upload na 4kb/s, download pa na max. Ce bi jst pisal ta program bi naredil, da po koncanem downloadu uploda se tam 20-30min preden zakljuci zadevo.
Wolverine-entertaining special effects masterpiece:)

BigFoot ::

BT sem neki malga uporablju že skor 6 mesecu nazaj, samo sem ga nehu. Pač mam dostop do en kup res hitrih FTPju na katerih se najde vse, tko da mi za BT kr dol visi :)
LG 77CX OLED TV; Marantz SR6010 7.2: 5x Focal Sib, 2x Focal Cub, 2x Focal
Little Bird; PS5, Xbox Series X, PS4 Pro, Xbox One, PS3, Vero 4K, Samsung
UBD K8500 4K UHD, Philips BDP2180/12

Tr0n ::

Wolverine: " If you don't share, eventually everyone else will stop talking to you." Se pravi cez cas, ce imas zelo nizek upload, bos imel tudi zelo nizek download. Edino ce je kr nekaj seederjev. Tudi v tem se razlikuje od ostalih P2P programckov.

Seveda pa lahko BitTorrent community deluje samo tako, kot si povedal. Po koncanem downloadu moras okno pustit odprto, da lahko se drugi ljudje dobijo datoteko. Zato pa obstajajo dolocene BT release skupine, ki najprej zadevo dobro zaseedajo (5 ali vec seederjev) in jo sele takrat dajo na voljo javnosti. Tako so downloadi cez 200 kb/sec zagotovljeni.

BigFoot: Se priporocam ;).

Zgodovina sprememb…

  • spremenilo: Tr0n ()

CaqKa ::

kje pa je tale supernova stran?
link?

Gandalfar ::

a bit of googling and no warez ;-)

CaqKa ::

pa pi* m*, kje si pa ti zdaj warez videl... z besedico nisem črhnil o njem.

kilergas ::

Stran je http://www.no_warez_on_this_forum_pleas... samo trenunto ne da kisika.

Zgodovina sprememb…

  • spremenil: Predator ()

globoko grlo ::

v bistvu bi moral sam program poskrbet da bi moral pustiti okno odprto enako dolgo kot si DLjal pa bi bila zadeva rešena, al pa vsaj kdaj je bil DL končan, da bi vedu kok cajta ga še pustit

aja, bigfoot:D

Zgodovina sprememb…

globoko grlo ::

aja, še neki, zdejle mi že cel dan en fajl stagnira na 99%, pa ni nobenga errorja, sam noče mi ga zvlečt, bom probal še restartat, sam dvomim da bo pomagalo

a je še kkšna druga rešitev

Tr0n ::

Preden zacnes snemat moras oz. je dobro .torrent preverit za seederji/leecherji (TorrentSpy). Ce noben nima celotne datoteke, potem je tudi ne bos dobil v celoti, edino ce je veliko leecherjev in vsi skupaj imajo celotno datoteko (ko startas download ti pise kolko procentov je na voljo od celotne datoteke). Lahko pa na strani, kjer si dobil .torrent nekoga prosis, ce ti reseeda.

globoko grlo ::

morm rečt da zdejle sprobavam BT++ zadevo in rula, leti 200K v povprečju, edin mot me ena stvar, na začetku je uploudal z ene 50K, zdejle pa max ene 10K, a noben folk noče tega fajla al je kj ne gre skupi, aja a lahko s to zadevo kj več fajlov naenkrat dol vlečeš al ne, če dan add torrent nič ne naredi, pa mam max 3 simDL naštiman pa vseen ne gre

če se komu da replayat pa nej, pa hvala za replay

globoko grlo ::

še eno pitance
zakaj mi bt++ prav da ne najde torrent fajla, če ša sm ga glih kar z desnim knofom kliknil in rekel odpri z bt++, pol pa prav da ne najde falja, wtf

Tr0n ::

BT++ je se dokaj buggy, zato ti priporocam BitTorrent EXPERIMENTAL. Lahko mas vec clientov naenkrat odprtih, ki se ti skrijejo v task bar ko minimiziras.

BigFoot ::

Tr0n> nisi edini :) če kej rabiš povej, morda ti lahko FXPjam (če maš FTP).
LG 77CX OLED TV; Marantz SR6010 7.2: 5x Focal Sib, 2x Focal Cub, 2x Focal
Little Bird; PS5, Xbox Series X, PS4 Pro, Xbox One, PS3, Vero 4K, Samsung
UBD K8500 4K UHD, Philips BDP2180/12

Gandalfar ::

wishmaster ::

evo vsaj en p2p program ki mi vleče dol z 460 kb/s en film.Pr muli mi je največ vleklo 20 kb/s,pri dc++ pa nekaj čez 300 kb/s.BT zakon.

Raw ::

@Tr0n:

Thanks, BT++ je res buggy, ma si nism najdu cajta za kaj bolsga dobit. Tale EXPERIMENTAL zadeva je kool.

Tr0n ::

By the way, people sometimes run clients hacked to not upload at all and still experience good download rates. Usually this is because they're downloading a file which has been available for a while and there are many clients which have finished downloading but been left running, so there's plenty of excess bandwidth to go around. Not uploading in a swarm which is still ramping up is generally ruinous for download rates.

No, ste slisali. Treba je cimvec uploadat, tudi ko koncate z downloadom. Statistike se vidjo na trackerjih, tako da to sluzi samo vam.

kilergas ::

JSt nestekam zdej prow nec. Poberem uni toret experimental in potem kje se najde kaj stufa? varjanta supernova ki je blo vse lepo , samo klik in wola ze pada dol.
Kje je treba iskat za uni experimental al kar je ???

Please HELP:'(

Zgodovina sprememb…

  • spremenilo: kilergas ()

Fury ::

isto. samo da suprnova ne dela zdele.

Tr0n ::

Zasebno sporocilo meni ali na moj email.

CaqKa ::

kaj pa takrat naredite ko napiše da je neki error pa da se s trackerjem ne more povezat?
pa kje je kašen resume pause button....

Tr0n ::

Ja, vcasih padejo trackerji dol. Ce govoris o FS strani, potem kr pusti download okno odprto in se bo cez cas konektalo.

Resume gumba ni. Enostavno kliknes na .torrent, ki ga se nimas v celoti in dolocis pot do delno presnete datoteke/direktorija in ti bo resumalo :).

Pause = cancel :).

OldSkul ::

Tale FS stran ima velik torrentov ali ne dela nobeden ker en error pokaže isti kot je že prej rekel Caqka.;( ;(

CaqKa ::

delajo samo morš malo potrplenjna met

Tr0n ::

Ja, majo neke probleme z FS trackerjem. Zadeva je na 100mbit liniji, samo je zgleda nepravilno nastavljena. Napaka se odpravlja.

Ahiles ::

Od vsej programov ki sem jih probal je bil burst najbolsi najman bugov kvalitetno sprogramiran.

http://krypt.dyndns.org:81/torrent/

CaqKa ::

kak naštelam speed pa upload limit enkrat za vselej da mi nebo treba vsakič posebej nastavlat....
čemu sliži oni torent spy? nisem videl neke posebne funkcije v njem.

Tr0n ::

Upload speed si na zacetku snemanja vedno rocno nastelas, glede na tvoje zmogljivost. Ce ti max upload zmanjsa download si ga pac malce zmanjsas. Vec uploadas, vec ljudi bo k temi downloadalo in tako bo skupen speed seveda vecji. Download limita ni, torej se vedno snema maksimalno mozno oz. koliko ti drugi ponujajo.

Ko posnames .torrent datoteko na disk, jo drag & dropas (ali desni gumb Open with TorrentSpy) v TorrentSpyja in ti bo povedal, koliko je vseh skupnih seederjev in koliko leecherjev, torej complete/incomplete ratio. Ce nima noben celotne datoteke, je ni mozno dobit. Se pravi, pred downloadom se prepricas, kako je stanje dolocenega .torrenta.
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