Client's Bandwidth

Discussion in 'Wireless Networking' started by Ohad, Dec 29, 2004.

  1. Ohad

    Ohad Guest


    I'm a programmer, and am programming a client-server application. I need the
    server to know what is the bandwidth of the client, i.e., the bandwitdh of
    the internet connection to the client's ISP. How can I get that information
    (I can implement it either on the server side or on the client side).

    Thanks a lot,
    Ohad Asor.
    Ohad, Dec 29, 2004
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  2. Ohad

    Leythos Guest

    Since "bandwidth" available to any client can change at any second, and
    does, it's not a good idea to base any decisions on that measure.

    As for your answer, other than the above, I don't have any idea.
    Leythos, Dec 29, 2004
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  3. In Microsoft they use similar test when they calculate link speed for
    applying Group Policy.

    Here is what they do. I'm sorry I couldn't find a link on Google, so I'm
    pasting the text


    Topic: How to Configure Refresh Rates for Group Policy

    Group Policy can detect a slow network links by using an algorithm. The
    algorithm that Group Policy uses to determine whether a link should be
    considered slow is as follows:

    1. The client computer that is attempting to process Group Policy sends a
    byte file to the authenticating domain controller, or server, which then
    returns the file to the client computer. The client computer measures the
    time it takes for the file to complete the round trip, and if it is less
    than ten
    milliseconds, the client computer assumes a fast link is present and sets
    fast link flag.

    2. If the round trip time in step 1 is more than 10 milliseconds, the
    computer saves the round trip time. Name this value time_1.

    3. The client computer sends a compressed file that is two kilobytes (KB)
    size to the server, which then returns the file to the client. The client
    computer again measures the time it takes the file to complete the round
    trip. Name this value time_2.

    The file that is sent to the server in step 3 is actually a JPEG file.
    JPEG files are compressed by definition. A compressed file is used because
    of the fact that data that is sent through a modem is frequently compressed
    and compressing the file would make the link appear faster than it really

    4. The client computer repeats step 3 two more times. Name these values
    time_3 and time_4.

    5. The client computer subtracts the value for time_1 from time_2, time_3,
    finally, from time_4. This subtraction is done to remove the overhead
    caused by session setup. Name these values delta_1, delta_2, and delta_3.
    Algorithm used by
    Group Policy to detect
    slow network links

    6. The average of the values for delta_1, delta_2, and delta_3 is
    Name this value avg.

    7. The connection speed is calculated as (the units are shown for clarity):
    (Connection Speed kilobits/second) = 2*(2 KB)*(8 bits/byte)*(1,000
    milliseconds/second)/(avg milliseconds)
    Because 2 KB of data move through each modem, Ethernet card, or other
    device in the link, once in each direction, there is a total of 4 KB, or 2
    the 2 KB, processed. This is why a leading factor of 2 is on the right side
    the equation.

    The connection speed calculated is the average of the upload and
    download speeds. In most situations, this average is the same as the
    speed itself. However, in some situations, the upload and download speeds
    different enough that you should take the speed difference into account. An
    example of different speeds is Asymmetric Digital Subscriber Line (ADSL).
    Using ADSL, you might have upload speeds of 128 kilobits per second (Kbps)
    and download speeds of 768 Kbps.

    To specify the threshold value for slow link detection for computer
    configuration Group Policy settings, you use the Computer
    Configuration\Administrative Templates\System\Group Policy\Group Policy
    slow link detection setting. To set this value for user configuration Group
    Policy settings, you use the User Configuration\Administrative
    Templates\System\Group Policy\ Group Policy slow link detection setting. The
    allowed value range is 0 to 4,294,967,200 Kbps. A value of zero indicates
    all links should be considered fast


    Dusko Savatovic
    Dusko Savatovic, Dec 29, 2004
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