Hybrid Optical-Electrical Data Center Networking: Challenges and Solutions for Bandwidth Resource Optimization

Abstract

Fast optical switching (FOS) is the most promising technology for data center networks (DCNs) to meet data rate requirements beyond 800 Gb/s, considering its transparent modulation format, low power consumption and dense port integration. However, FOS, leveraging optical packet switching (OPS) technology, is hardly compatible with the electrical switches that are widely used in the current hybrid optical/electrical switching data center networks (Hoe-DCNs). The diversity of topologies and multi-switching granularity increases the risk of service disruption and reduces bandwidth efficiency. Based on the IP-over-OPS system, we propose bandwidth resource optimization techniques with the aid of hybrid polling contention resolution and microsecond-level load balancing in Hoe-DCNs. We first present an optical switching architecture to show its performance characteristics in the context of nanosecond-level FOSs in terms of resource management and setup optimization. Based on the fabricated FOS structure, we discuss the emerging problem of packet contention and introduce a bufferless scheduling solution. The characteristics of load balancing for Hoe-DCN are then investigated and evaluated by simulating Hoe-DCNs. Finally, the numerical results are given and analyzed based on a large-scale DCN testbed.