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Thread: Measure DSL speed?

  1. #1
    Vic Dura
    Guest

    Measure DSL speed?

    Hello All,

    I have a question about how download DSL speed is measured.

    Previously I had 1.5Mb DSL service. When I went to a site such as
    SpeakEasy <http://www.speakeasy.net/speedtest/> to measure my d/l
    speed, it would show approximately 1.1 - 1.3 Mb which is what I would
    expect. However when I would use a .bat script in a WinXP console
    window to measure the speed I would only calculate about half that
    speed.

    The .bat script works as follows:

    1) turn on a timer
    2) use ftp to download a 1.5MB file from the server of my ISP.
    3) turn off timer & save elapsed time
    4) calculate d/l speed from the known file size and d/l time

    I've recently upgraded to 3Mb service and I have seen my d/l speeds
    double. However I still see the same relative disparity between the
    two methods of d/l speed measurement as described above; i.e. the
    speed measured at SpeakEasy is about 2.9Mb/sec but the speed
    calculated by the script is about 1/2 that.

    Can anyone offer any insight as to why the large disparity?

    Thanks
    --
    At first they laugh at you, then they ignore you, then they fight you, then you win.

  2. #2
    Bert Hyman
    Guest

    Re: Measure DSL speed?

    In news:4q3tp4961dntlhbkar86gp6ojiee2mku6s@4ax.com Vic Dura
    <vpdura@hiwaay.net> wrote:

    > Can anyone offer any insight as to why the large disparity?


    You're including all the Windows and program overhead in your timing.

    It takes time for Windows to load and close your FTP program, and a
    significant amount of time for your FTP program to look up and connect
    to the remote server, negotiate with the remote server to open the file
    and then save the downloaded file on your PC at the end.

    I suppose you could try to swamp the overhead by downloading a very
    large file, but the overhead will still be there.

    --
    Bert Hyman St. Paul, MN bert@iphouse.com

  3. #3
    Bert Hyman
    Guest

    Re: Measure DSL speed?

    In news:oIVmFqPdSe4P-pn2-Efcdz6Tm3wbK@otis "Peter"
    <SOMEONE@orcon.net.nz> wrote:

    > There are so many variables that are added in there it almost seems
    > pointless to do any "testing" because all testing is moot. If you
    > REALLY want to know what your Hardware NEGOTIATED Line rate is, then
    > let your Hardware tell you what speed it obtained.


    Testing can be useful if you have reason to think that something funny
    is going on upstream.

    My router usually trains up at 6592/896 Kbps and I usually get 5Mbps
    downloads from close-in, capable sites.

    When things seemed to go sour a few months ago, I was able to use test
    results to first convince myself that something was going on and to get
    The Phone Company and my ISP to look into things.

    Unbelievable as it seems, The Phone Company actually admitted that
    they'd over-committed the DSLAM at the local central office, and my ISP
    did some load balancing on their circuits and things have been fine
    since then.

    --
    Bert Hyman St. Paul, MN bert@iphouse.com

  4. #4
    Peter
    Guest

    Re: Measure DSL speed?

    Hi Vic,

    > I have a question about how download DSL speed is measured.


    Unfortunately, you are chasing shadows there.....;-)

    > Previously I had 1.5Mb DSL service. When I went to a site such as
    > SpeakEasy <http://www.speakeasy.net/speedtest/> to measure my d/l
    > speed, it would show approximately 1.1 - 1.3 Mb which is what I would
    > expect. However when I would use a .bat script in a WinXP console
    > window to measure the speed I would only calculate about half that
    > speed.


    There are so many variables that are added in there it almost seems
    pointless to do any "testing" because all testing is moot. If you
    REALLY want to know what your Hardware NEGOTIATED Line rate is, then
    let your Hardware tell you what speed it obtained. For a DSL service,
    most DSL H/W provides a status display similar to this one (please
    excuse the formatting) -

    ATU-R (DS) ATU-C (US)
    Modem Status: Showtime (DMTDSL_SHOWTIME)
    DSL Mode: ITU G.992.1 (G.DMT)
    ITU STD NUM: 0x01 0x01
    Vendor ID: 'ALCB' 'BDCM'
    Vendor Specific: 0x0000 0x9191
    Vendor Country: 0x00 0xB5
    Capacity Used: 99% 39%
    Noise Margin: 12.0 dB 29.0 dB
    Output Power: 16.5 dBm 11.5 dBm
    Attenuation: 57.5 dB 31.5 dB
    Defect Status: None None
    Last Fail Code: None
    Selftest Result: 0x49
    Subfunction: 0x02
    Interrupts: 52250 (78 spurious)
    Activations: 280
    SW Version: 3.8129
    FW Version: 0x1A04

    Interleave Fast Interleave
    Fast
    Speed (kbps): 1344 0 160
    0
    Reed-Solomon EC: 499 0 0
    0
    CRC Errors: 7 0 0
    0
    Header Errors: 10 0 0
    0
    Bit Errors: 0 0
    BER Valid sec: 0 0
    BER Invalid sec: 0 0


    The line to note is this one -
    Speed (kbps): 1344 0 160
    0

    Also useful is tihs one -
    Noise Margin: 12.0 dB

    The SPEED tells me that this ADSL line has negotiated a DS
    (DOWNSTREAM) connection speed of 1.344 Mb, and an US (UPSTREAM)
    connection speed of 160Kbps, and the NOISE MARGIN tells me that the
    Router NEGOTIATE a rate that is likely to be LOWER than the rate that
    is possible ON THIS LINE. Ideally, the NOISE MARGIN should be
    somewhere around 4 - 8db to be closer to optimal (note there is no 1
    guaranteed value that is truly optimal) This can be for a number of
    reasons, some inside your (or your ISP) control, some outside you
    control. EG Currently its extremely wet outside and such weather can
    play havoc with the performance of the Copper cable in our area, so
    the displayed rate is likely to be lower what than I am normally able
    to get (I normally get about 2.0Mb Down, 160 Up), which is close to my
    contracted service, I get less due to my large distance from the
    DSLAM.

    That is the most accurate form of line speed between YOUR house and
    your CONNECTION point and it is EXACTLY correct! Nothing else is in
    the equation. Thre are 2 things to note -
    1. This is an ATM (DSL) line rate so the framing on that line will
    be in ATM cell (block) size of 53 Bytes, using a 48 Byte payload,
    meaning effectively the USER visible operating speed is 1.334Mb LESS
    about 5/53 or something like 9-10%.
    2. Usually, DSl H/W continually evaluates its connection parameters
    and adjusts the line signaling to obtain values that usually work
    best. It is CRITICAL to understand that copper in the ground is NOT a
    static environment, there are MANY variables that mean it's
    performance can and will vary, sometimes by wide margins. ALL of this
    is usually OUTSIDE your control, all a user can do is ensure they
    operate their hardware within its working parameters, and these days
    there is very little required from the user in this respect.
    ..
    > The .bat script works as follows:
    >
    > 1) turn on a timer
    > 2) use ftp to download a 1.5MB file from the server of my ISP.
    > 3) turn off timer & save elapsed time
    > 4) calculate d/l speed from the known file size and d/l time


    For really accurate readings you are adding in too many uncontrollable
    variables into your figures to worry about trivia like this. Please
    dont waste your time...

    HOWEVER, having said all that the REAL issue for users is the
    bandwidth between YOUR machine and the destination Server for EACH
    site you are trying to communicate with, with whatever SERVICE you are
    trying to reach. All thee factors will affect performance and are near
    impossible to calculate on a public network such as the internet.

    The reality is that it all comes down to the question "Is your ISP
    delivering the service they promised?",and that can be a really tough
    question to PROVE, let alone answer.

    > Can anyone offer any insight as to why the large disparity?


    Simple, the methodology used for calculating these figures is flawed,
    and its like a cat chasing its own tail. This does not stop cats
    desiring to catch their own tail.....;-)

    I hope this helps.........................pk.


    --
    Peter from Auckland.


  5. #5
    Robert Redelmeier
    Guest

    Re: Measure DSL speed?

    Vic Dura <vpdura@hiwaay.net> wrote in part:
    > The .bat script works as follows:
    >
    > 1) turn on a timer
    > 2) use ftp to download a 1.5MB file from the server of my ISP.
    > 3) turn off timer & save elapsed time
    > 4) calculate d/l speed from the known file size and d/l time
    >
    > I've recently upgraded to 3Mb service and I have seen my d/l speeds
    > double. However I still see the same relative disparity between the
    > two methods of d/l speed measurement as described above; i.e. the
    > speed measured at SpeakEasy is about 2.9Mb/sec but the speed
    > calculated by the script is about 1/2 that.
    >
    > Can anyone offer any insight as to why the large disparity?


    Try a larger file. At 3 Mbps, a 1.5 MB file takes 4 seconds raw.
    Most ftp transfers take a while to startup.

    -- Robert


  6. #6
    me@tadyatam.invalid
    Guest

    Re: Measure DSL speed?

    Vic Dura <vpdura@hiwaay.net> wrote in
    news:4q3tp4961dntlhbkar86gp6ojiee2mku6s@4ax.com:

    > Hello All,
    >
    > I have a question about how download DSL speed is measured.
    >
    > Previously I had 1.5Mb DSL service. When I went to a site
    > such as SpeakEasy <http://www.speakeasy.net/speedtest/> to
    > measure my d/l speed, it would show approximately 1.1 - 1.3
    > Mb which is what I would expect. However when I would use a
    > .bat script in a WinXP console window to measure the speed
    > I would only calculate about half that speed.
    >
    > The .bat script works as follows:
    >
    > 1) turn on a timer
    > 2) use ftp to download a 1.5MB file from the server of my
    > ISP. 3) turn off timer & save elapsed time
    > 4) calculate d/l speed from the known file size and d/l
    > time
    >
    > I've recently upgraded to 3Mb service and I have seen my
    > d/l speeds double. However I still see the same relative
    > disparity between the two methods of d/l speed measurement
    > as described above; i.e. the speed measured at SpeakEasy is
    > about 2.9Mb/sec but the speed calculated by the script is
    > about 1/2 that.
    >
    > Can anyone offer any insight as to why the large disparity?
    >
    > Thanks


    Vic,

    Let NetMeter do the measuring.

    http://www.metal-machine.de/readerror/

    J
    --
    Replies to: Nherr1professor2doktor31109(at)Oyahoo(dot)Tcom

  7. #7
    Vic Dura
    Guest

    Re: Measure DSL speed?

    On Tue, 24 Feb 2009 02:41:57 GMT, me@tadyatam.invalid wrote Re Re:
    Measure DSL speed?:

    >Vic,
    >
    >Let NetMeter do the measuring.
    >
    >http://www.metal-machine.de/readerror/
    >
    >J


    Thanks for the link, and thanks again to all for the comments.
    --
    To email me directly, remove CLUTTER.

  8. #8
    thank you very much for this info, was a real help

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