Collaborative Network Configuration in Hybrid Electrical/Optical Data Center Networks

Recently, there has been much effort on introducing optical fiber communication to data center networks (DCNs) because of its significant advantage in bandwidth capacity and power efficiency. However, due to limitations of optical switching technologies, optical networking alone has not yet been able to accommodate the volatile data center traffic. As a result, hybrid packet/circuit (Hypac) switched DCNs, which argument the electrical packet switched (EPS) network with an optical circuit switched (OCS) network, have been proposed to combine the strengths of both types of networks. However, one problem with current Hypac DCNs is that the EPS network is shared in a best effort fashion and is largely oblivious to the accompanying OCS network, which results in severe drawbacks, such as degraded network predictability and deficiency in handling correlated traffic. Since the OCS/EPS networks have unique strengths and weaknesses, and are best suited for different traffic patterns, coordinating and collaborating the configuration of both networks is critical to reach the full potential of Hypac DCNs, which motivates the study in this paper. First, we present a network model that accurately abstracts the essential characteristics of the EPS/OCS networks. Second, considering the recent advances in network control technology, we propose a time-efficient algorithm called Collaborative Bandwidth Allocation (CBA) that configures both networks in a complementary manner. Finally, we conduct comprehensive simulations, which demonstrate that CBA significantly improves the performance of Hypac DCNs in many aspects.