Efficient software-defined passive optical network with network coding

The huge increase in broadband service requires much more bandwidth than ever before; however, due to the cost sensitivity, it is not possible to pursue high transmission rate blindly in the access network, which requires us to consider how to improve network efficiency. In this paper, a software-defined passive optical network architecture with network coding (NC) is proposed to reduce downstream bandwidth consumption and thus increases the throughput and network efficiency. To flexibly implement the coding operation on local peer traffic, the NC pair management scheme is provided and keeps the compatibility with the current multi-point control protocol (MPCP) in a single optical line terminal (OLT). Considering the trends in OLT pooling and the requirement of smooth network upgrade, software-defined networking (SDN) techniques are applied in the NC-based passive optical networks. Through re-arranging the affiliations between the OLTs and optical network units (ONUs), the local traffic between peer ONUs will be led from non-NC-supported OLTs to NC-supported OLTs, and then the downstream efficiency will be still quite high even in a hybrid OLT pool. The experiments and evaluation results show that, the software-defined passive optical networks with NC reduce nearly 50 % occupied downstream bandwidth, when there is local traffic between peer ONUs, even in a hybrid OLT pool.