Performance Assessment and Comparison between Star-ring based and Tree based EPONs

In this paper, a meaningful star-ring based EPON architecture is proposed to reduce the local traffic transmitted from ONUs (Optical Network Units) to OLT (Optical Line Terminal) which can provide the bandwidth efficiency. One of ONUs is assigned as a Sub-OLT to control the partial traffic in the ring. In addition, the ONU structure is modified in all optical process to reduce the optical-electrical conversion delay. This paper proposes a star-ring dynamic bandwidth allocation (SRDBA) scheme on star-ring based EPON, which the SDBA (star dynamic bandwidth allocation) in OLT responds all ONU’s EF traffic and Sub-OLT’s traffic by tree topology; and the RDBA (ring dynamic bandwidth allocation) in Sub-OLT handles all AF and BE traffics from each ONU circulated along the ring topology. Simulation results show that the proposed scheme bandwidth efficiency, and reduces traffic delay even system traffic in heavy loading.