Bittorrent Oddity

Discussion in 'NZ Computing' started by s.t.e.v.e., Feb 18, 2006.

  1. s.t.e.v.e.

    s.t.e.v.e. Guest

    I've noticed that when I set my bit torrent client to upload at 18kbps, it
    will then - usually - have a download rate of about 13kbps.....and I
    generously end up downloading one iteration and uploading 1.5 or two or
    even more.

    But if I lock the upload rate down to about 10kbps, the upload rate rapidly
    climbs to 30kbps, 40kbps or more.....and is sustained there.

    That seems odd to me......or is it? Maybe bit torrent is feeding rapidly to
    people to who have little capacity to share (10kbps...)......and making
    maximum use of people in a (relatively) better position to share (18kbps)
    with more peers?????
     
    s.t.e.v.e., Feb 18, 2006
    #1
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  2. s.t.e.v.e.

    s.t.e.v.e. Guest

    s.t.e.v.e. wrote:

    > But if I lock the upload rate down to about 10kbps, the upload rate
    > rapidly climbs to 30kbps, 40kbps or more.....and is sustained there.


    Oops...I meant the download rate climbs.....
     
    s.t.e.v.e., Feb 18, 2006
    #2
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  3. s.t.e.v.e.

    ~misfit~ Guest

    s.t.e.v.e. wrote:
    > s.t.e.v.e. wrote:
    >
    >> But if I lock the upload rate down to about 10kbps, the upload rate
    >> rapidly climbs to 30kbps, 40kbps or more.....and is sustained there.

    >
    > Oops...I meant the download rate climbs.....


    It's a sad fact of life that here in NZ with our non-broadband upload speeds
    the upload on bittorrents have to be throttled right back to get good upload
    speeds. In fact, I find that anything over 5kB/s up and the down really
    suffers. Of course, that means I have to leave it running most of the day
    just uploading to try to get a reasonable ratio. I use Azureus and there's
    an option to have no set upload speed (ie unlimited) when not downloading.
    It's good for when your download's finished.

    Bittorrent downloads can have a lot of 'overhead'. Azureus tells you how
    much of your data each way is 'protocol'. For my current session (Actrix,
    rate-limited to 64kbps each way) the download is 41.72MB, 18.66MB, or 41.7%
    of which is 'protocol'.

    The protocol goes both ways and if you're uploading at anything near your
    actual speed there isn't enough bandwidth to establish downloads and send
    the data back to the guy you're downloading off.

    So... Yeah... Until we get a higher upload speed, to optimise your download,
    5kB/s is the optimum upload speed. As I said, you can always upload later /
    earlier to keep a reasonable ratio. However, try as I might, I have trouble
    keeping my ratio above .5

    Cheers,
    --
    ~misfit~
     
    ~misfit~, Feb 18, 2006
    #3
  4. s.t.e.v.e.

    Mark C Guest

    "s.t.e.v.e." <> wrote in
    news::

    > I've noticed that when I set my bit torrent client to upload at
    > 18kbps, it will then - usually - have a download rate of about
    > 13kbps.....and I generously end up downloading one iteration and
    > uploading 1.5 or two or even more.


    If you have Orcon Bitstream, the max upload of 128kbps is =
    ~16kByte/sec. If you set your bit torrent upload to 18kByte/s, then
    the line speed is the limit and you are saturating your upload.

    You need to leave enough upload bandwidth so that ACKs
    (acknowledgments) for the data you are downloading can be sent. If
    your upload is saturated with bittorrent, the ACKs get delayed and
    your download stalls.

    > But if I lock the upload rate down to about 10kbps, the upload
    > rate rapidly climbs to 30kbps, 40kbps or more.....and is
    > sustained there.


    This is because 10kByte/s leaves ~6kByte/s headroom for the ACKs.
    (10+6 = 16).

    You should also make sure your TCP RWIN is set appropriately:
    http://www.dslreports.com/faq/tweaks
    http://www.dslreports.com/tweaks
    (Select "Jump to topic" and try Tweaktester and RWIN.)

    Mark
     
    Mark C, Feb 18, 2006
    #4
  5. s.t.e.v.e.

    s.t.e.v.e. Guest

    Mark C wrote:

    >
    > You need to leave enough upload bandwidth so that ACKs
    > (acknowledgments) for the data you are downloading can be sent.  If
    > your upload is saturated with bittorrent, the ACKs get delayed and
    > your download stalls.


    Thanks.

    That makes sense in pure network terms alone....and certainly accounts for
    what I have been seeing.
     
    s.t.e.v.e., Feb 18, 2006
    #5
  6. s.t.e.v.e.

    s.t.e.v.e. Guest

    ~misfit~ wrote:

    > So... Yeah... Until we get a higher upload speed, to optimise your
    > download, 5kB/s is the optimum upload speed. As I said, you can always
    > upload later / earlier to keep a reasonable ratio. However, try as I
    > might, I have trouble keeping my ratio above .5


    Thanks....

    I usually set a completed download to "dial/isdn" speed (5k upload)....and
    let it run for a couple of days......and often until it has a ratio of 2:1.

    Especially if it is early in the lifecycle of the particular torrent and
    there are many leechers / few seeds.
     
    s.t.e.v.e., Feb 18, 2006
    #6
  7. s.t.e.v.e.

    Gordon Guest

    On Sat, 18 Feb 2006 23:19:04 +1300, s.t.e.v.e. wrote:

    > ~misfit~ wrote:
    >
    >> So... Yeah... Until we get a higher upload speed, to optimise your
    >> download, 5kB/s is the optimum upload speed. As I said, you can always
    >> upload later / earlier to keep a reasonable ratio. However, try as I
    >> might, I have trouble keeping my ratio above .5

    >
    > Thanks....
    >
    > I usually set a completed download to "dial/isdn" speed (5k upload)....and
    > let it run for a couple of days......and often until it has a ratio of 2:1.
    >
    > Especially if it is early in the lifecycle of the particular torrent and
    > there are many leechers / few seeds.


    All a seeder has is all the pices of the file. They might be uploading at
    a very low rate. Given enough "leechers", a term which is somewhat
    incorret if people are giving as much as they give, all the parts of the
    file will be avaliable.
     
    Gordon, Feb 19, 2006
    #7
  8. s.t.e.v.e.

    Gordon Guest

    On Sat, 18 Feb 2006 21:48:42 +1300, ~misfit~ wrote:

    > Bittorrent downloads can have a lot of 'overhead'. Azureus tells you how
    > much of your data each way is 'protocol'. For my current session (Actrix,
    > rate-limited to 64kbps each way) the download is 41.72MB, 18.66MB, or 41.7%
    > of which is 'protocol'.


    Part of which can be/is corrupted slices. 41% seems somewhat high.
     
    Gordon, Feb 19, 2006
    #8
  9. On Sun, 19 Feb 2006 16:53:19 +1300, Gordon wrote:

    > On Sat, 18 Feb 2006 21:48:42 +1300, ~misfit~ wrote:
    >
    >> Bittorrent downloads can have a lot of 'overhead'. Azureus tells you how
    >> much of your data each way is 'protocol'. For my current session
    >> (Actrix, rate-limited to 64kbps each way) the download is 41.72MB,
    >> 18.66MB, or 41.7% of which is 'protocol'.

    >
    > Part of which can be/is corrupted slices. 41% seems somewhat high.


    41% can be possible if most of the seeds and leechers are limiting their
    upload speed, causing the protocol to be a higher percentage of the data
    traffic than normal. I mean, if there are lots of peers with comparitively
    few seeds, and with most of them dialup, and with a large percentage of
    the peers with a low percentage of the torrent, then the seeds will have
    to be spreading the data around quite widely and at dialup speed. That
    means each peer won't be getting much data in one hit until the relative
    completion rates of the peers increase sufficiently to enable more data
    being shared.

    I've seen torrents ebb and flow in their available speed to the extent
    that I've stopped a torrent, waiting for a more opportune moment to
    resume it.

    IOW, nothing to worry about, but for bandwith efficiencies sake, maybe
    stop that torrent for a while until it's a little faster.


    A Nice Cup of Tea

    --
    A: because it messes up threading
    Q: why should I not reply by top-posting?
    A: No.
    Q: Should I include quotations after my reply?
     
    A Nice Cup of Tea, Feb 19, 2006
    #9
  10. s.t.e.v.e.

    ~misfit~ Guest

    Gordon wrote:
    > On Sat, 18 Feb 2006 21:48:42 +1300, ~misfit~ wrote:
    >
    >> Bittorrent downloads can have a lot of 'overhead'. Azureus tells you
    >> how much of your data each way is 'protocol'. For my current session
    >> (Actrix, rate-limited to 64kbps each way) the download is 41.72MB,
    >> 18.66MB, or 41.7% of which is 'protocol'.

    >
    > Part of which can be/is corrupted slices. 41% seems somewhat high.


    Yeah, that's 'cause I was rate-limited back to 64kbps I think. I notice that
    there's always a high percentage of 'protocol' when the download is very
    slow (and I'm uploading as well). When I'm on a hot one the 'protocol'
    percentage is very low.
    --
    ~misfit~
     
    ~misfit~, Feb 19, 2006
    #10
  11. s.t.e.v.e.

    ~misfit~ Guest

    Gordon wrote:
    > On Sat, 18 Feb 2006 23:19:04 +1300, s.t.e.v.e. wrote:
    >
    >> ~misfit~ wrote:
    >>
    >>> So... Yeah... Until we get a higher upload speed, to optimise your
    >>> download, 5kB/s is the optimum upload speed. As I said, you can
    >>> always upload later / earlier to keep a reasonable ratio. However,
    >>> try as I might, I have trouble keeping my ratio above .5

    >>
    >> Thanks....
    >>
    >> I usually set a completed download to "dial/isdn" speed (5k
    >> upload)....and let it run for a couple of days......and often until
    >> it has a ratio of 2:1.
    >>
    >> Especially if it is early in the lifecycle of the particular torrent
    >> and there are many leechers / few seeds.

    >
    > All a seeder has is all the pices of the file. They might be
    > uploading at a very low rate. Given enough "leechers", a term which
    > is somewhat incorret if people are giving as much as they give, all
    > the parts of the file will be avaliable.


    Yeah, you still gotta be careful. I've tried to get a coulple of older
    torrents now and they both had no seeders, even after a couple weeks of
    'downloading'. Just a whole bunch of leechers all with, say, 87.6% of the
    file. Shame really, probably a lot of bandwidth wasted as most of those
    people will never complete the file and will delete it eventually. That's
    why I selectively decide what to seed. If I've successfully got an older
    torrent and there is still demand for it I'll seed that (or 'those' as the
    case is) in preference to other, more available files.
    --
    ~misfit~
     
    ~misfit~, Feb 19, 2006
    #11
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