Station stops sending

[gd]

Hi all,

I've designed an experiment where there is a client sending a file to a server (with the BulkSendApplication). The client is connected via WiFi to an AP and the AP is connected to the server via a csma link. There are also several background stations sending background traffic to the AP, using the OnOffApplication. I do not simulate any interference. I find two things odd:

• When plotting the throughput of the client and background stations, I noticed that there is one station who apparently just stops sending (ie., its throughput becomes zero); the red line (station 10.2.1.4) in the plot. I've noticed the same behaviour (stations dropping out) in experiments with another number of background stations also.
• Also, the yellow station's throughput (10.2.1.3) also drops significantly during the period 120-130s. Considering the DCF mechanism and collisions, indeed there could be a drop of throughput for a second, but +/- 10 seconds? Isn't that long?
  

Can someone help me out finding the exact causes/explanations? I've added the plot and the script file (it's a large file...).

Thanks in advance,

Glenn