Efficient bandwidth allocation algorithm for ethernet passive optical networks

Abstract

Bandwidth allocation is one of the critical issues in Ethernet passive optical networks (EPONs). To achieve good network performance and thus provide guaranteed network service to end users, an EPON system must employ an efficient bandwidth allocation algorithm to dynamically allocate the limited bandwidth of the upstream transmission channel among multiple optical network units (ONUs). In the paper, an efficient bandwidth allocation algorithm for an EPON system is proposed. The proposed algorithm uses the multipoint control protocol (MPCP) defined by the IEEE 802.3ah Task Force to arbitrate the transmission of multiple ONUs, and incorporates a dynamic bandwidth allocation (DBA) scheme that makes use of the excessive bandwidth of lightly loaded ONUs to meet the bandwidth demand of heavily loaded ONUs. To improve bandwidth utilisation under high traffic load, an effective scheduling control mechanism is also incorporated to address the idle period problem. Through simulation experiments, it is shown that the proposed algorithm can significantly improve the network performance in terms of packet delay, queue length, and throughput under high traffic load as compared with a well-known DBA algorithm in the literature.