Illustrator :: Automatically Adding Specific Shape At Points Along Path?

i'm trying to build an easy way to create something like the following network graphic in Illustrator:

I basically want to create a brush or some other automatic method for adding a specific shape (in this case a circle) at every point a long a path. It would be nice if I could easily move around points on a path without have to move all of the circles independently.
 
I tried creating a pattern brush where the circles were the corner elements but depending on the angle of the corner the shape would get distorted.