Monitor Network Internet Traffic?

I am having problems with my internet connection. I am part of a network and I need a software to track the much each computer is consuming in terms of bandwidth in real time. Ideally it would list all the computers on the network, their current download and upload speed if there is any internet activity. Its not a problem if i need to install a client software on all the computers. That way, when my internet speed drops, I can tell whether there is a problem with the network hardware or if it is simply that the computers on the network are using the internet.