Not sure what your asking here. BMW assist helps you in the case of a breakdown etc. They send a bloke in a 5 series Tourer usually kitted out with everything to help you get going. They help you home, to a garage or to your destination.
The Tracker system only operates through the company "Tracker" There are other inferior brands. Usually BMW fit only Tracker.
There are Three types of tracker : see here :
http://www.tracker.co.uk/home.php
or page 9 of this brochure :
http://www.tracker.co.uk/misc/brochures/Compan yBrochure.pdf
Hope this helps.
Usually BMW fit these. However there are other devices - RAC Tracker is one.