BandwidthD is described as 'tracks usage of TCP/IP network subnets and builds html files with graphs to display utilization. Charts are built by individual IPs, and by default display utilization over 2 day, 8 day, 40 day, and 400 day periods' and is a Network Monitor in the Network & Admin category. There are five alternatives to BandwidthD for a variety of platforms, including Linux, BSD, Mac, Windows and VirtualBox. The best alternative is nload, which is both free and Open Source. Other great apps like BandwidthD are vnStat (Free, Open Source), ntop (Free, Open Source), CacheGuard-OS (Paid) and darkstat (Free, Open Source).
nload is a console application which monitors network traffic and bandwidth usage in real time. It visualizes the in- and outgoing traffic using two graphs and provides additional info like total amount of transfered data and min/max network usage.
vnStat is a console-based network traffic monitor for Linux and BSD that keeps a log of network traffic for the selected interface(s). It uses the network interface statistics provided by the kernel as information source.
NTop is a hybrid layer 2 / layer 3 network monitor, that is by default it uses the layer 2 Media Access Control (MAC) addresses AND the layer 3 tcp/ip addresses. ntop is capable of associating the two, so that ip and non-ip traffic (e.g.