Cyclic polling-based dynamic wavelength and bandwidth allocation in wavelength division multiplexing passive optical networks

Cyclic polling-based dynamic wavelength and bandwidth allocation algorithm supporting differentiatedclasses of services in wavelength division multiplexing (WDM) passive optical networks (PONs) is proposed.In this algorithm,the optical line terminal (OLT) polls for optical network unit (ONU) requests to transmitdata in a cyclic manner.Services are categorized into three classes:expedited forward (EF) priority,assuredforwarding (AF) priority,and best effort (BE) priority.The OLT assigns bandwidth for different prioritieswith different strategies.Simulation results show that the proposed algorithm saves a lot of downstreambandwidth under low load and does not show the light-load penalty compared with the simultaneous andinterleaved polling schemes.