My system is continuously uploading and downloading at the same speed. What does this mean?

I am using ubuntu 14.04. Recently I started noticing that my system was uploading and downloading something in the background(I did not initiate this). The upload and download speeds were quite high and also equal. See screenshot below from network monitor: I installed nethogs and tried to catch the culprit but then I got something weird from that as well. PID USER PROGRAM ? root 172.xx.yy.96:34716-31.13.78.35:443 I tried to check for the program using the port but the following did not give any output: suhas:~$ sudo netstat -nlp | grep 34716 suhas:~$ sudo lsof -n -P -i +c 13 | grep "34716" suhas:~$ fuser 34716/tcp And guess what the ip 31.13.78.35 means. Facebook(https://31.13.78.35:443) . I really don't understand what is going on. I have tried stopping all programs which were running but that did not seem to have any effect on the upload/download. It goes on for some time and stops on its own. Edit: tcptrack screenshot(port 35740):