GPON dynamic MAC protocol to support differentiated services

Abstract

The Gigabit-capable passive optical network (GPON) has become an attractive and promising solution for the broadband access network. In this paper a novel dynamic bandwidth assignment protocol is proposed to both facilitate the efficient sharing of the upstream channel resource and support differentiated services over GPON. A new concept for the optical network unit bandwidth reporting procedure is developed instead of the conventional reporting of current queue status. The development of a balance transferring enables a bandwidth register and transfer mechanism in which the reported but bandwidth-unassigned requirements from previous allocations can be tracked and manipulated at the optical line termination. Dynamic bandwidth compensation is achieved through the balance transferring mechanism. The combination of the new reporting procedure and the balance transferring mechanism is incorporated into a prioritised resource allocation to accommodate differentiated services. It also efficiently supports the operation of the GPON encapsulation method. Fairness is supported by a proportional allocation scheme among various demands from different customers. The proposed MAC protocol is implemented using the OPNET Modeler platform. Simulated performance characteristics are presented and the GPON dynamic protocol is analysed under varying self-similar traffic loads.