I will discuss line defects in certain supersymmetric quantum field theories. A line defect can be characterized by the BPS states that can be bound to it, the so called framed BPS states. I will discuss methods to study framed BPS states using an effective supersymmetric quantum mechanics based on a certain graph, called quiver.
If there is time I will discuss the action of certain operators, called quantum monodromies, on the space of line defects.