Job terminating after sometime due to RFC Communication Failure

Hi experts,

I am facing a scenario in which I am extracting data from BW system and loading to Oracle. It has 4-5 left joins. Left table has 1.7 million rows.

I have up and running RFC connection and the job execution starts properly. Problem is that it loads only 6 lakh records in approx 1300-1400 secs and then terminates. It gives the RFC Communication Failure error after loading particular no. of records or after running for a particular period of time. I am confused on this. Tried searching on google but my error is nowhere mentioned.

I need some urgent help on this. Please give your inputs. It would be highly appreciated. Here's the error :

Thanks in advance!