KNemo is described as 'displays for every network interface an icon in the systray. Tooltips and an info dialog provide further information about the interface. Passive popups inform about interface changes. A traffic plotter is also integrated' and is an app in the Network & Admin category. There are five alternatives to KNemo for Windows, Linux and Mac. The best alternative is BitMeter OS, which is both free and Open Source. Other great apps like KNemo are DU Meter (Paid), Smart Traffic Meter (Free, Open Source), BWMeter (Paid) and NetGraph (Free).
Smart Traffic Meter is a Linux network usage monitor. The program shows real-time graphs and reports. Smart Traffic Meter runs as a system daemon and displays all information in a web user interface accessible through a web browser.
NetGraph is a free to use network bandwidth monitor. It shows real-time information about the state of network traffic in a visual display format selected by the user. NetGraph can monitor the data flows of wired, Wi-Fi and mobile connections.