[PLUG] 3G Data Transfers, WAS: Alternative to using split / cat for FTPing large file to remote location?

Tom Sharples tsharples at qorvus.com
Wed Apr 27 18:55:00 UTC 2011


I believe this is a problem with all carriers altho we use Verizon. Basic issue is competition with cellphones and that's a big problem esp. during rush hour. Throughout the day, we've measured upload speeds as high as 450kbs and as low as 8kbs. 

We do have a number of these systems out there (not with 10mp cams tho) and this problem shows up anytime you're in an urban or suburban area. Performance is actually much better in rural areas (if you can get a signal), presumably because there's not as much cellphone traffic.

----- Original Message ----- 
  From: Michael R 
  To: Tom Sharples ; General Linux/UNIX discussion and help; civil and on-topic 
  Sent: Wednesday, April 27, 2011 10:25 AM
  Subject: Re: [PLUG] 3G Data Transfers, WAS: Alternative to using split / cat for FTPing large file to remote location?


  Tom Sharples wrote:
  > Hello,
  > 
  > We're building a wireless 3G IP camera system that will FTP a large
  > (2.5Mbyte) 10 megapixel jpeg image every 30 minutes to a remote server, for
  > use in a time-lapse image application. Using a cron job, we pull the image
  > from the attached IP cam via curl http://<local cam IP address>/img.jpg
  > >/tmp/image.jpg, and then FTP it to the remote server. This works fine when
  > the 3G connection is working well (around 300-400K upload bandwidth). But
  > when the 3G connection slows to a crawl, which happens multiple time each
  > day, the FTP transfer hangs or times out

  Well that's interesting.  Is this all on one 3G network or multiple carriers?  Are the 3G slowdowns consistent with respect to time of day?  Do you you have multiple camera points?

  Please tell more.



  -- 
  Michael Rasmussen
  http://www.jamhome.us/
  Be Appropriate && Follow Your Curiosity



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