Recently much attention has been given to the Differentiated Services (Diffserv) Architecture, which is proposed to offer quality of service (QoS) in IP
networks. Assured Forwarding (AF) provides a better quality service than best effort under moderate conditions to traffic within the assured class. Various
mechanisms have been proposed to implement the necessary per hop behavior. In this work, these mechanisms are reviewed in detail and a literature survey is given. Then a simulation study about fairness is presented, evaluating the diffserv behavior for the assured and best effort traffic classes in case of responsive and
non-responsive traffic mixture with and without an active queue management scheme. The study also investigates the effect of using a rate adaptive traffic shaper on
fairness.

Keywords: Quality of Service (QoS), IP Networks, Differentiated Services (Diffserv) Architecture, Fairness, FRED, FMRED, Rate Adaptive Shaper.