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Uploading/Downloading large sized files with Background Transfer

    Question

  • Hi,

    Using the sample application code.msdn.microsoft.com/windowsapps/Background-Transfer-Sample-d7833f61 I am able to upload and download small sized files and it works fine.

    Regarding the maxUploadFileSize I have increased it to 500 MB and observed that either the upload or download does not work for files greater than 100 MB and after 4 to 5 MB it shows "Error not found".

    What is the reason for this. Is there any limit on the upload/download with this Background Transfer. Can I use this to transfer at least 100 MB between the client and the server.

    Thanks,

    Rajesh.


    Wednesday, September 17, 2014 10:47 AM

Answers

  • Hi Rajesh,

    Please ref to Vishal's suggestion, test with a local web browser to determine where is the root cause.

    As I know Background transfer operations continue even if your app is suspended or even terminated, however it could be limited by BackgroundTransferCostPolicy enumeration 

    --James


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    Friday, September 26, 2014 9:53 AM
    Moderator

All replies

  • Error that you have mentioned seems to be coming from Server, nothing to do with the background task. Try to download large files from Internet Explorer (or any other Web Browser). If things do not work there please post this on ASP.NET forum.

    Here is MSDN Link to understand the limits:

    http://msdn.microsoft.com/en-us/library/windows/apps/xaml/hh977056.aspx

    Here is some extract

    When running on battery (DC power), background tasks also have a network data usage limit. This limit is a function of the amount of energy used by the network interface, so it varies depending on the device and network environment - but it can be estimated.

    The following table characterizes network data throughput, assuming a resource constrained WiFi network capable of 1Mbps of average data throughput. To estimate the correct limit, multiply by the average megabits per second (Mbps) of the connection. For example, an app can use 25 MB of data every 2 hours on a 10Mbps WiFi connection if it's placed on the lock screen. The example WiFi interface assumes minimal interference.

    Refresh period 15 minutes 2 hours Daily
    Data limit (on lock screen) 0.469 MB n/a 45 MB
    Data limit (not on lock screen) n/a 0.625 MB 7.5 MB

     

    Note  The network data usage limit is lifted when the device is plugged in (AC power), but the CPU usage quota still applies. Similarly, the CPU and network resource constraints are suspended for an app's background tasks while the user is interacting with it in the foreground.


    -- Vishal Kaushik --

    Please 'Mark as Answer' if my post answers your question and 'Vote as Helpful' if it helps you. Happy Coding!!!

    Wednesday, September 17, 2014 11:04 AM
  • Hi,

    I tested this with a external server and found that the web config file had to be modified as per this article(http://weblogs.asp.net/jeffwids/from-iis6-maxrequestlength-to-iis7-maxallowedcontentlengthfile-specifying-maximum-file-upload-size)

    I found that the upload was working fine for large sized files but the download always restricted to 4883 KB. The file size is actually 7744 KB

    What exactly has to be done and where to fix this issue.

    Thanks,

    Rajesh.

    Monday, September 22, 2014 2:03 PM
  • Hi Rajesh,

    Please ref to Vishal's suggestion, test with a local web browser to determine where is the root cause.

    As I know Background transfer operations continue even if your app is suspended or even terminated, however it could be limited by BackgroundTransferCostPolicy enumeration 

    --James


    <THE CONTENT IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND, WHETHER EXPRESS OR IMPLIED>
    Thanks
    MSDN Community Support

    Please remember to "Mark as Answer" the responses that resolved your issue. It is a common way to recognize those who have helped you, and makes it easier for other visitors to find the resolution later.

    Friday, September 26, 2014 9:53 AM
    Moderator