Medium access control layer performance modelling for APONs

Combining asynchronous transfer mode over a passive optical network (APON) can provide broadband services as defined by the International Telecommunications Union (ITU). The medium access control (MAC) layer is of primary importance to the access scheme as it controls the flow of traffic in the access network. It is therefore beneficial to model MACs for APONs to provide a performance evaluation without the expensive and time consuming job of building prototypes. This paper describes the simulation and performance comparison of a selection of proposed MAC schemes for APON, using the block oriented network simulator (BONeS) simulation software. The protocols simulated are all based on the TDM/TDMA technique, each with a different polling scheme, namely; demand, cyclic and semi-static. Both the development of a simulation strategy using a common simulation platform and the implementation of the permit distribution algorithm for the MAC protocols are described. The simulations show that the performance characteristics of the MACs are to a large degree comparable. There is, however, a superior performance in the parameters measured by the protocol based on demand polling.