How can I get the current network traffic broken down by subnet

Question

I'm trying to modify one of my extensions that shows network traffic from my computer (For an indicator). I'd like to be able to quantify how much of the network traffic I see is coming/going to the internet, and how much is exchanged with my local subnet.

Is there any way to make this distinction in Ubuntu using e.g. netstat?

Answer 1

Assuming you could obtain current network traffic, broken down by subnet, and put that process into a shell script, you could then install indicator-sysmonitor and add your script to the indicator.

I also happened upon bandwidthd which may help.