Abstract: With the rapid development of cloud computing and the constant increase of the number of servers, data center network (DCN) faces great challenges, such as scalability, cost, power consumption, bandwidth and so on. This paper proposes an arrayed waveguide grating router (AWGR) based hybrid opto-electrical DCN architecture. The AWGR is utilized to provide optical wavelength routing for elephant traffic and the electrical packet switch is used for mice traffic switching. The AWGR is a passive optical device and can potentially increase network reliability, reduce network power consumption and configuration delay compared with optical circuit switches. This paper also proposes three optical source plans for the network architecture: plan one only contains fixed laser diodes (FLDs) at edge switches, plan two contains hybrid fixed and tunable LDs, and plan three only contains tunable LDs (TLDs). This paper performs both numerical analysis of network cost and power consumption and theoretical analysis of network performance. Numerical results show that as the number of servers increases, the cost and power consumption of three plans all increase. Among them, the cost and power consumption of plan three increase much faster than the other two. Network performance simulation results show that the network throughput and wavelength request blocking probability of plan two are approaching to those of plan three, and they are much better than plan one. In a word, plan two has a balanced performance and cost tradeoff.

Key words: data center network (DCN), hybrid opto-electrical architecture, arrayed waveguide grating router (AWGR), optical wavelength routing, electrical packet switching

摘要： 随着云计算需求与服务器数量的不断增长，数据中心网络（data center network，DCN）面临可扩展性、低成本、低能耗、高带宽等一系列挑战。提出了一种基于阵列波导光栅路由器（arrayed waveguide grating router，AWGR）的光电混合数据中心网络架构。该混合架构由AWGR提供大容量光波长路由，由电分组交换机提供突发分组交换，同时满足大象流量和老鼠流量的需求。AWGR是无源光器件，将有效降低网络能耗，提高网络可靠性，与光电路交换机相比，可降低配置时间延迟。分析了在架顶交换机上分别采用全固定波长激光器（方案1）、混合固定波长激光器和波长可调谐激光器（方案2）、全波长可调谐激光器作为光源（方案3）的3种架构方案。对3种架构方案的成本和能耗进行了数值分析和计算，同时对网络性能进行了理论分析与仿真。成本和能耗数值分析结果显示：3种架构方案的成本与能耗随着服务器数量的增加不断增长，方案3增长的速度最快，方案1增长的速度最慢，方案2介于两者之间。网络性能仿真结果显示：在不同网络负载情况下，方案2架构的网络吞吐量和波长请求阻塞率与方案3接近，远高于方案1，因此混合固定波长激光器与波长可调谐激光器的方案2具备较好的性价比。

关键词: 数据中心网络（DCN）, 光电混合架构, 阵列波导光栅路由器（AWGR）, 光波长路由, 电分组交换