Software defined flexible and efficient passive optical networks for intra-datacenter communications

Facing the huge traffic challenge, optical networking shows great advantages on capacity and energy issues. However, the efficiency and flexibility are not satisfactory to the data center networks, especially for intra-datacenter communications. This article reviews the typical architectures of data center networks, and suggests that TWDM-PON system can be used in the edge layer and aggregation layer in the datacenter networks. It proposes a software defined flexible and efficient passive optical network, combining the software defined technology and network coding, for intra-datacenter communications. Network coding is applied to increase the downstream bandwidth efficiency and overcome network bottleneck, and software defined technology provides the flexibility on wavelength assignment according to traffic statistics dynamically. To increase more efficiency, a seamless DBA (S-DBA) scheme and an ONU grouping algorithm are proposed to fully utilize the upstream idle time and minimize the traffic entering into the core layer of the datacenter networks. They realize flexible scheduling and resource allocation both in time domain and wavelength domain. The experimental simulations indicate that the proposed schemes and algorithms provide low delay, good fairness, increased efficiency and network flexibility.