Dialup doesn't use available bandwidth

Discussion in 'Computer Support' started by Howard Heflin, Mar 21, 2007.

  1. I have dial up and use a US Robotics V-Everything for my connections.

    I have no problem connecting to the net; but when I download a file, I
    find that it will start out using most of the bandwidth available
    according to the Windows Task Manager. However, then the process seems
    to throttle to the point that it is using only a maximum of 30 - 43% of
    the bandwidth.

    I'm using XP-Pro SP2 on a dual core 64 AMD with 2G of RAM

    Any one want to give me a clue why this occurs? Does ELNK throttle
    downloads on dial up?
    Howard Heflin, Mar 21, 2007
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  2. Howard Heflin

    Mr. Arnold Guest


    Circuit switching dominates the public switched telephone network or
    PSTN. Network resources set up calls over the most efficient route. That
    might mean a call from New York to San Francisco goes through switching
    centers in San Diego, Chicago, and Saint Louis. But no matter how
    convoluted the route, that path or circuit stays the same throughout the
    call. Got it? One call, one circuit. It's like having a dedicated
    railroad track with only one train, your call, permitted on the track at
    a time.


    The connection can start switching for best path on bottlenecks, which
    leads to packet loss, re-transmission of packets, transmission slow down
    by the sender, etc, etc.

    The link with the article explains what happens with data in a TCP/IP
    connection, really starting around figure 7 as to why things work they
    work and the measures taken to make it work.

    Mr. Arnold, Mar 22, 2007
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  3. Howard Heflin

    why? Guest

    If your ISP has V-Everything and the line is at optimum performance and
    the server could supply files as fast as request you will get the max
    download rate you can.
    Depends on the far end and everything in between.
    What process, unless... oh well it maybe doesn't matter because you
    might mean the Networking tab, which isn't a great guide anyway.
    30-43% of what max, if it's 56K not bad, if it of 256K it's bad.
    Ask them?

    Or if it's not them, ask every intermediate provider up to the admins of
    the server you download from.

    You could have put - speeds dial up earthlink in your subject line so
    maybe earthlink users may have noticed.

    why?, Mar 22, 2007
  4. Thanks to both of you for the feed back.

    FWIW its 30-42% max of 56Kb or around a max download rate of 17Kb to
    24Kb. That's not what I would call good. :-(
    Howard Heflin, Mar 23, 2007
  5. Howard Heflin

    why? Guest

    You could have snipped a bit, or not bottom posted 3 lines at the end.

    Do remember 56k was a in theory maximum, not really obtainable in
    practice. You may find old posts in 24HSHD mentioning speeds.

    IIRC, 6/7+ years ago since I had dialup, it was about the time V92 came
    out. ISP had the industrial rack versions of the USR V.92 hardware. I
    upgraded my modem to a USR 56K V.92 + drivers and the speeds went up to
    37,500 / 48,000 speeds.

    You have set the serial COM port baud rate to 115200?

    A lot of people did this-

    V.92 56000 baud, set COM port speed to closest (whatever it was). Except
    that *limits* the amount of data transferred between the PC/modem, not
    the modem/ISP. i.e. you are slowing down the PC/modem data rate.

    With the modem, [buffers / compression] and UART on the the PC serial
    port it (I always used hardware external modems, never winmodems) will
    transfer data to/from the PC at 115200 baud.

    why?, Mar 23, 2007
  6. Yeh, I have the modem set to 115200 so I'm not sure exactly what your
    are saying I should do to improve things?
    Howard Heflin, Mar 23, 2007
  7. Howard Heflin

    why? Guest

    Some people set the COM port speed to 57000 (just looked up values).

    Well you didn't mention it at first, so as you have it set to 115200
    that's that sorted, you don't need to change it. Otherwise the
    improvement would have been change it to 115200.

    Driver issue?

    Maybe it's just the phone line.

    why?, Mar 23, 2007
  8. This all leads me to wonder if DSL will be much of an improvement if its
    a phone line issue. :p Is there any relatively easy way to determine
    if it's a line issue?
    Howard Heflin, Mar 24, 2007
  9. Howard Heflin

    r72392 Guest

    The problem is TCP ack packets not getting through. Use a program
    that prioritizes the TCP control traffic and you will get close to
    100% line utilization (Traffic Shaper XP is a good freeware one).
    r72392, Mar 24, 2007
  10. Howard Heflin

    why? Guest

    I would suspect that if you research local ISP, DSL support forums you
    will find lots of info.

    Ask the phone company to test the line.
    why?, Mar 24, 2007
  11. Thanks for the info. :)
    Howard Heflin, Mar 27, 2007
  12. Thanks; but my main issue seems to with downloading via HTTP not FTP. I
    have found a couple of FTP utilities that help by making multiple
    connections to the download site. However, many of the downloads are
    via HTTP. They seem to behave differently.

    I installed the Traffic Shaper XP s/w; but that did not seem to effect
    those HTTP downloads nor any of the "streaming" video issues. While they
    do tend to stay above 50%, they fluctuate quite a bit with periodic
    drops to below 10% and get some major drop out. Some streaming sound
    from radio stations seems to work just fine while others types of
    streaming sound do not.

    It's just odd that the network load starts out at full usage and then
    drops to less than 50%.

    I think that I'm going to have to check with my phone carrier (Verizon)
    to have them check the line as was suggested by "Why" in the other part
    of this thread.
    Howard Heflin, Mar 28, 2007
  13. Howard Heflin

    why? Guest

    Ah some new info then, you didn't mention before.
    Traffic shaping works best when the other end (kit in between) knows
    about it as well, XP has it's own QoS built in anyway.

    HTTP is more likely to be affected by a proxy somewhere, or even a
    policy on the remote end.

    It seems odd for ACKs to be affecting HTTP but work fine on FTP, email ,
    general browsing (that's okay?) or anything else you do.

    TCP/IP takes care of all the communications at a level much lower then
    the application, HTTP, FTP , POP3, SMTP etc, other things

    [ optional - OSI Stack, applications at the top layer 7 and TCP/IP
    follow it exactly, but sort of fits into Transport / Network.
    See function description on the table,
    The upshot of all of that is your FTP application does - an application
    request - open connection to server, this is converted from the
    application command to data / session / connection / how to get there
    and so on. ]

    Traffic shaping isn't much of an issue for 1 user more so on 56K dialup
    you generally can't do 3 or 4 streaming video / sound , downloading
    sessions at once. Without multiple PCs you are also unlikely to want to
    ensure 1 PC used for games gets 45-90% of available bandwidth while an
    other gets 5% to download etc.

    There are quite a lot of articles on this sort of thing, TCP tuning I
    have never used it. You may want to have a look and compare opinions see
    if it's worked for others. Most likely asking in your ISP newsgroups if
    other uses have done any of the changes.


    List of articles / tools

    [ also optional - Note on XP QoS,
    Your ISP connection -to a Windows Server running QoS management - PCs
    running QoS.
    As the ISP end and everything else isn't QoS it doesn't help much
    generally, however if you set the policy at the server it manages the
    QoS to each PC hence what's going over the ISP link, so it's effectively
    the throttle device for each PC. ]

    why?, Mar 28, 2007
  14. Thanks for even more information. I think that I'll check with the
    phone company before I start getting down into the insides of this thing.
    Howard Heflin, Mar 31, 2007
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