Another reason, is we are using a thin pipe, and we are using quite a lot of bandwidth. Which I think we are student, there is not much we can do. Either way, I have not much of a choice, but to track it.
Webmin have a utilities to gather bandwidth usage statistics, which have one problem, take s a lot of cpu cycle, and slow down a server and I have to kill it. Until I figure out how to reconfigure it.
MRTG can do that too. except, to check out each host, you need to have snmp agents install on them. Which I can't because it is a dorm, and the computer is private property. So here, mrtg is monitor the server only. Life is so simple, when this is a work space.
On the other hand, linux have a few utilities for this as well. The one I use, is iftop. Best describe as top for network. It is in repository for most distro. It can be used to check bandwidth usage of each host.
To call it, just type
iftop -i ethxyou should get all the data from that interface. In a ncurse interface.
But the data don't stay, when you restart the program it will start again. Nevertheless, still useful. For someone who can't use snmp for the task.