We can monitor the bandwidth usage by using the third party too like Bandwidth manager on the Linux server.
Login in to the server as a root user and follow the steps.
[/usr/local/src]tar -zxf bwm-ng-0.5.tar.gz
[/usr/local/src/bwm-ng-0.5]#./configure; make; make install
The bwm-ng command will show you the following result.