Typical Problem with torrents

[mrbgupta]

hi all,

i am going through a typical problem with torrent files.
i use the latest version of utorrent.

i have posted a file to share in a different forum i.e. i am the initial seeder.
i am uploading lot of data but it is affecting very low towards availability.
as far as i know availability represents percentage of the file leechers have downloaded. i.e. if availability is 1.234 then leechers have downloaded 23.4% of the file (am i right? if not please correct me).i have till now uploaded 50% of the file size but the availability is showing only 1.300.

my question is that is it the way torrent client works in ? can't i get the 1st leecher who completes downloading by just uploading 100% of the file size?

in fact one of my friend told me that he had to upload about 4 GB to seed a 1.36 GB file so that leechers could complete downloading.but he could not help me anyway as he is also in need of help.

is it relates to bandwidth or internet connection?
i use Dataone UL connection(256 kB/s).i get download speed around 30 kB/s and upload speed around 6.5 kB/s .

so i request please help me in this matter.

[deadpulse]

Yes man you are right but that is not a problem in torrents. It happens because when you are a single seeder everybody takes packates from you and so you see the your upload ratio going up but if you see in actual case no one has got the full file from you. See let me explain you like this...

If you are uploading a 100 Mb file and there is 50 leechers... you will see your upload ratio more than 1.5 or anything like that. Because, everyone is downloading from you. You are the only source. if every leecher downloads 1 Mb from you you will see you have uploaded 50 Mb but in actual case everybody has got only 1 Mb of data on their system. Got my point?? So, until and unless anyone completes the download on their system they can't start seeding and so you have to upload it till the 2-3 seeders are formed.

[mehulved]

Even though you have uploaded 50% of the file, it doesn't just go to a single client it's spread over different clients, who get different pieces of data. It so happens that the clients having the rest 20% are offline(or their torrent client isn't running), so you only see 1.300

[aryayush]

And what does availability mean? If a file has an availability of 0.823, does it mean that the whole swarm combined has only got 82.3% of the file, so unless a seeder joins the swarm, no one can get the full file? I think it means that. I have not read it anywhere, just tried to apply some logic. Please correct me if I am wrong.

I myself can see a problem with my theory. If this is the case, then why does the availability go beyond 1.000 for famous torrents?

[Rollercoaster]

the availability is expressed as X.Y

here X means the no. of complete copies of the data(including partial collectons between peers)
Y(0.Y) is the incomplete average part of the whole data being shared, i.e if all the complete copies are removed then a maximum of Y*100% of completion will be reachable.

say u have a 2 mb torrent with 4 pieces of 512kb each, say A,B,C,D
and say there are 3 peers and a seeder say P,Q,R,S

suppose P has A,B,D
suppose Q has B
suppose R has C,B
suppose S has A,B,C,D obviously, he is a seeder

Now the total availabitity is 2.250
here X=2 (1 for seeder and 1 for partial part total, i.e P,Q,R themselves have one piece each so they make a whole)
and y = 0.250(the remaning part, that is 2 copies of B after removing the compete set above)

Availabitity for B is 4
Availability for C is 2 etc.etc.

If X is greater then total no of seeders, so now even if all seeders are removed then all peers will be able to complete the download(and then X will then be 1)

Hope it is clear now.

Note- availabitity is calculated for the connected peers only.

[aryayush]

Whoa! Sorry but I did not understand a word of it.

[mehulved]

It's like this.
Availability is in the form of xxx.yyy
xxx is the no. of seeders. So, if there are 2 seeders active the availability will be 2.yyy.
yyy is the % availability with other peers who are active. So, say if those active peers have 50% of the file compeleted then it will show as 2.500.
Now if say out of those peers only one had 50% and the rest had 30% or less and the one with 50% completed is not active at the moment. the availability will be 2.300.

<Off Topic>
rollercoaster what's with the torrent client you were working on? Is it still in development or done away with?
</Off Topic>

[Rollercoaster]

Originally Posted by tech_your_future

It's like this.
Availability is in the form of xxx.yyy
xxx is the no. of seeders. So, if there are 2 seeders active the availability will be 2.yyy.

no thatz wrong. xxx is the totan no of seeders + total no of complete piece collections between peers too. You can see this in anytime when downloading, compare the seeds and availability

Originally Posted by tech_your_future

yyy is the % availability with other peers who are active. So, say if those active peers have 50% of the file compeleted then it will show as 2.500.
Now if say out of those peers only one had 50% and the rest had 30% or less and the one with 50% completed is not active at the moment. the availability will be 2.300.

yyy is the % of data left after removing all the data represented by XXX. It works like in set theory.

Originally Posted by tech_your_future

<Off Topic>
rollercoaster what's with the torrent client you were working on? Is it still in development or done away with?
</Off Topic>

still working.. and because it is a hobby, developement is very slow.. besides i am working alone on it

[mehulved]

Originally Posted by Rollercoaster

no thatz wrong. xxx is the totan no of seeders + total no of complete piece collections between peers too. You can see this in anytime when downloading, compare the seeds and availability

I was unsure on that point, but should have said that. thanks for clearing it up.

Originally Posted by Rollercoaster

still working.. and because it is a hobby, developement is very slow.. besides i am working alone on it

If you don't mind me suggesting, why don't you open up the code, you might get a couple of people working on it. So, you will get the development work going faster and learn a couple of things. Well the final decision is yours of course.

[Rollercoaster]

Originally Posted by tech_your_future

If you don't mind me suggesting, why don't you open up the code, you might get a couple of people working on it. So, you will get the development work going faster and learn a couple of things. Well the final decision is yours of course.

not at all man. but i am trying to desing a new functionality for bittorrent network(seems too ambitious, right?), and i can only go opensource and get good feedback once i have a basic layout. so i am going to wait for sometime. besides i am working on asp.net web developement now a days so... bittorrent is on the back page