Much like top and htop, the iftop command is used to resource usage on your system. Specifically, it monitors the bandwidth of active ethernet interfaces. When applied to the situation I described above, you can run the iftop command to see what is actually using the bandwidth across the data replication interface. This can be incredibly efficient when you consider how long it might take you to come to that conclusion by troubleshooting the interface itself. There is no problem, just an excess of activity on the interface.