If your Internet connection has a bandwidth limit then having installed a network bandwidth monitor is a must have. Ubuntu’s system monitor can let you monitor networks too but it does not keep a track of the data.
Now there are few tools that you can use in Ubuntu but most of them are command-line based ones. But if you prefer a GUI tool then NTM is worth trying.
*. Monitors both Local and Internet networks (including the connection durations).
*. Saves the data automatically thus you can retrieve them later.
*. Shows daily, hourly, weekly, monthly bandwidth usage.
*. Change update intervals.
*. Shows current transfer speed (both download and upload).
*. Add/Remove network “slots”.
*. A separate reports window.
*. Threshold support: By using this feature we can easily set NTM to automatically disconnect when a certain usage limit is reached.
*. Run in the notification area.
*. Supports Qt/KDE, Gnome, Xfce and Unity.
You can install the Network Bandwidth Monitor (NTM) in Ubuntu 11.04 Natty Narwhal, 11.10 Oneiric Ocelot, 10.10 and 10.4 (plus all the way down to 9.04!) by first downloading the “.deb” package from here.
Then as usual, double click on it to open using the Ubuntu Software Center which should take care things for you.
I’d very much like to give a big thanks to the developer for creating it. Enjoy.