To install this indicator applet:
Press Ctrl+Alt+T on keyboard to open the terminal. When it opens, choose one method from below and run the commands one by one:
Compile from source (github.com):
sudo apt-get install build-essential libgtop2-dev libgtk-3-dev libappindicator3-dev git-core git clone git://github.com/mgedmin/indicator-netspeed.git cd indicator-netspeed make sudo make install
Once installed, start the applet via:
You need to manually add this applet into Startup Applications (open it from Unity Dash).