Bits,Torrents,Seeds,Port Forwarding Info.
Some useful bit of information which I thought of sharing.Not many might know of torrents,downloading and stuff especially port forwarding.
BitTorrent is just a way of sharing/downloading files. Sometimes, you just download files from a server (one-way) through your browser. You also have download managers to manage this e.g. DAP (Download Accelerator Plus), IDM (Internet Download Manager), FDM (Free Download Manager)
Then there's P2P = Peer-to-Peer where you don't depend on a central server, but you share the load among fellow downloaders (peers). You download the file from people who already have the file and after it is done, you share the file for whoever may be looking for it. KaZaa, Sharaaza, eDonkey are some clients which help you there.
Now, BitTorrent can be considered as an advanced P2P.
Assume you want to download a legal, shareable copy of a movie of size 1.36 GB and later you would like to share it with your friends.
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Step-1: You first visit a site which maintains a list of .torrent files. There are plenty of sites which do that and you can find .torrent files even through Google. But, wait a minute, let me tell you what this file is like. It is a very small file, around 20 KB or so in size. It contains name, file-list of the movie you are planning to download and the location of the tracker server. This tracker server helps to keeps track of IPs which have the complete file and which IPs are downloading this file.
Step-2: So now, you have downloaded this small .torrent file (perhaps with a download manager). You need to find a Torrent client now - the software which should manage your download. I use uTorrent, which is very light in file size and should be fine for basic usage. There are many more like Azureus, BitComet etc.
Step-3: We have added the torrent file into the torrent client. Now, here's where the fun part begins - the client gets statistical information from the tracker and displays it to you e.g. In this case, 1 person has the complete file (and is called a seeder), while you are the one who requires the file (and you are called the leecher). In BitTorrent, each file is actually 'n' number of pieces. Assuming the .torrent file specifies 1 MB for each piece, we need to download 1400 pieces. The client usually displays IPs of your seeds and leechers/peers and info about how much data is being passed from them to you or vice versa.
Step-4: The first piece (e.g. Piece #440, which is 1MB in size) has been received by your torrent client now. Then a customs check-up takes place to see if the data is as expected. SHA-1 hash keys are used for this and the .torrent file has the list of hashes for every single piece. If the hash of the downloaded piece does not match with the one in the .torrent file, it is dropped and redownloaded.
Step-5: A few hours have passed now. We have received around 200 pieces now (not in any particular order - actually, BitTorrent picks pieces based on its availability - rarest is downloaded first). At this time, Leecher-2 adds the same .torrent file to his torrent client. Time for your client to start uploading pieces now. The tracker tells the new client that there is 1 seed and 1 peer using this .torrent file already. The new client will now be receiving pieces from both you (Leecher-1) and Seeder-1.
Step-6: If Seeder-1 takes a break now, Leecher-2 and you can still keep transferring pieces as you will both have pieces the other person didn't have after the transfers with Seeder-1. You should know that BitTorrent works on a tit-for-tat policy. Give a piece-take a piece. :-)
Step-7: Download completed. You are now promoted to Seeder-2. You can now keep uploading to Leecher-1 and any other leechers who would come in future
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NOTE
TILL THE EXTENT POSSIBLE, DOWNLOAD A FILE WITH MAXIMUM SEEDS AND PEERS AND LESS LEECHES AND ALWAYS SEE THE CONTENTS OF THE FILE BEFORE DOWNLOADING...ALSO CHECK THE COMMENTS IF THERE IS ANY MENTION OF VIRUS
1 comments:
Gud Info ..
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