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Aren't clients supposed to exchange pieces this-for-that, 1:1?


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Go ahead and say I don't understand the protocol, because no, I don't.

Here's the thing that I don't get:

I understand that seeds philantropically give out pieces without asking for

anything in return, they have 100% of the file and seed out of pure kindness,

but I really would like my client to be a little more greedy and actually ask

for something in return for the gigs it is throwing out at other clients.

Example: as I look at the torrent I'm dealing with at present,

I have uploaded 2850 MB to a certain peer (who has 70%) and downloaded 72 MB.

Another peer:

2830 MB uploaded, peer has also 70%, and I've downloaded 179 MB.

My upload speed is 10 times higher than my download.

I could accept that my client hands out a certain number of freebies, like

10-20 pieces or so, just to give the remote client something to trade with,

but throwing out 30 times more pieces than I get, that's something I understand

a seed would do but not a client that's supposed to get something back.

I want my client to say, ok, now you've got 20 pieces from me and I'm not even

a seed, now it's time for you to give something back to me or else trading's off.

I think that would be a logical way for a client to act, but as I said, I obviously

do not understand the way the protocol is working for my benefit in this case.

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~2800 MB to two peers?!? You must have a fat pipe. It takes me days to get out that much TOTAL, lol. Uhm, well for starters, I have to say thanks for providing uploading to your swarm. :) To get to your question, uhm I don't know. Are you connecting to enough peers where the upload slots has to switch between peers regularly? Are you the 2nd highest available in the swarm? Generally speaking broadband is not based for the upload conscious (especially so in the US where you can get up to 12 Mbit down, but still be stuck with a puny .5 up), so if you see 'comcast.net' or 'rr.com' or 'verizon.net' that is what is going on. If this is still the case while you are regularly switching peers you can limit the upload more if you like on that torrent. What is your upload anyway? From the sheer size of those figures I'm guessing at least 5 Mbit up. There are two basic ways to run a torrent client, low torrents, high volume, or high torrents low volume. The former helps when initial-seeding, and the latter can help to keep limping swarms alive with little micro-management from you. The problem with the disparity is that "reasonable bandwidth in a reasonable timeframe" is subjective. If you have 256Kbps upload and are putting out 28KiBps and seeding 50 MiB to ONE peer in the time it takes to download 200 MiB, you have given essentially ALL of your upload to that one peer, but you still would see a 4:1 ratio in the bandwidth exchanged. I know that doesn't help you feel better for getting so little from peers, but remember your upload is someone else's download.

Also if you would like to know about uTorrent in general Ultima compiled a superb manual found on the guides page or under µManual below.

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Thanks for your reply, jewelisheaven.

I have a 24/8 Mbit connection (Swedish cable), 6 seeds, 21 peers.

Maybe I have too many upload slots?

I have the setting 23 slots, and increase # of slots if upload < 90%.

So the trick is to set a number of slots lower than number of peers?

Will check out the Ultima guide, thanks!

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Well since moast have a slower line then you. You will always upload more then you download before your done. In rare cases when you get another high speed peer or seed you might complete it before.

As for this for that. You have to look at it as the more you upload the less peices the others have to transmit to eachother and hence more of their upload will go to you. The more of the pices everyone has that you do the more of the pices you don't have will be transfered. If you understand that.

Unfortunatly if you want to download the torrent the fastest your best off uploading as much as you can to as many you feel comfortable with. The reason being that the protocol is designed so that the program prioritise peers that upload to you. But I don't know how the uTorrent is configured as regards to speed. They have design it so that you can't upload 0.5-1 KB/s to a peer and get prio as leechers did in the early days.

Myself I have 30-50 Mbit and use 100 connections per torrent and 25 upload slots per torrent. On slow public torrents I generally increase it to 100 upload slots. On private sites ppl generally have better connections and seed more so if you want fast downloads it's there you want to be.

Oh and ofcourse the more upload slots the more strain on your harddrive ofc and it must access diffrent pieces all the time.

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Uploading faster than 10 KiloBYTES/sec PER upload slot will almost guarantee you won't be getting as much back as download speed...since most people CAN'T upload that much at once. (Assuming 4 total upload slots, they'd need over 40 KiloBYTES/sec total upload speed...or 384 kilobits/sec.)

On a 24/8 mbit connection...you should have about 800-900 KiloBYTES/sec usable upload speed in µTorrent. You'd need at least 80 total upload slots (counting ALL your torrents) to make each one get only about 10 KiloBTYES/sec. Since the torrent you're trying only had 21 peers...that's not possible and you're likely giving a huge chunk of your upload to the 1 peer which limited THEIR upload speed lower than their overload maximum (which reduces their download speed). The other peers may have dumb settings and/or "unlimited" upload speed, which KILLS their ability to download fast...and ironically SLOWS their upload speed down too!

tit-for-tat can't work correctly if you're rate-limited by slow seeds. Since you're on a very fast connection, the seeds are probably sending the majority of their upload bandwidth to you. So the other peers are predominately downloading from you...and have little-to-nothing to give in return, since the seeds are mostly uploading to you. I'd expect most of the peers on that torrent to have roughly the same percentage...and they're slowly creeping upwards.

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I feel I'm beginning to understand how this works.

Thank you all for helping out.

I had in the back of my mind that even though, as an example, peers would

upload with only 5 kbyte, if there are 100 peers that's 500 kbyte total all of a sudden.

I was wondering as I saw the peer list why there was a peer that was getting a consistent 200kbyte from me and I was getting 5kbyte back instead of my client

uploading at smaller rates to a larger number of peers, enabling tit-for-tat better(?).

(I thought initially that was because s/he was using BitComet and there was foul play

somehow involving that specific client.)

As for the seeds uploading mostly to me because of my fast connection, I don't

know if I can relate to that, many of the seeds were either not uploading at all or

uploading at very low rates.


So if I got the message, I would need in the range of 80 peers/slots to get back as much as I'd like from my connection, well I really shouldn't whine so much because

on busier torrents than the one I wrote about I get quite nice rates.

I get that as broadband connections are mostly asymmetrical, I need a lot of peers

who give a little each.

Now I'm going to RTFM to find out how exactly the slots/peers relationship

works, if every peer has only one slot or can use multiple slots, don't know but

will find out.

Will read your post Switeck a few more times because the description of the mechanics

was well formulated but I didn't get how unlimited upload speed can be a bad thing,

my individual torrents have unlimited upload but I have a global cap of 900 kbytes.

Will RTFM. But sleep first. 4 a.m.

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You don't have as big a problem because your upload total is "huge" relative to the amount needed to surf the web without noticeable delays. You may not even be able to find people who can download as fast as you can upload. But if you only have 40-43 KiloBYTES/sec upload speed max like me, setting to unlimited can cripple internet web browsing. (And I have more upload speed than many, if not most!)

Also, at unlimited upload speed, uTorrent is CONSTANTLY overloading the upload pipe and the ISP will randomly delete some packets to keep the speeds in check...even over-compensating to try to force the speeds down. So not only are you losing critical SYN-ACK download reply packets, but you're also losing so much that you'll get better upload speeds by setting upload speed max to the highest smooth upload rate the connection can typically sustain. TCP flow control is a complete disaster under overload conditions, which is exactly the situation for many BitTorrent users who set their upload speed to unlimited.

"many of the seeds were either not uploading at all or uploading at very low rates."

They probably use the default setting of 4 upload slots...and probably connected to most if not all the peers on that torrent. So 20 peers with 4 upload slots means uploading to any given peer only 20% of the time. Once again, their upload speeds are probably like mine...and they may have multiple torrents going at once. Given only 4 active torrents with 4 upload slots each and an upload speed max of 40 KiloBYTES/sec, that's only 2.5 KiloBYTES/sec each. If you get 5, you're beating the average. :P

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