Experimental Demonstration of Multidimensional Switching Nodes for All-Optical Data Center Networks

Abstract

Abstract-This paper reports on a novel ring-based data center architecture composed of multidimensional switching nodes. The nodes are interconnected with multicore fibers and can provide switching in three different physical, hierarchically overlaid dimensions (space, wavelength and time). The proposed architecture allows for scaling in different dimensions while at the same time providing support for connections with different granularity. The ring topology reduces the number of different physical links required, leading to simplified cabling and easier link management, while optical bypass holds the prospect of low latency and low power consumption. The performance of the multidimensional switching nodes has been investigated in an experimental demonstration comprising three network nodes connected with multicore fibers. Both high capacity wavelength connections and time-shared subwavelength connections have been established for connecting different nodes by switching in different physical dimensions. Error-free performance (BER<10 -9 ) has been achieved for all the connections with various granularity in all the investigated switching scenarios. The scalability of the system has been studied by increasing the transmission capacity to 1 Tbit/s/core equivalent to 7 Tbit/s total throughput in a single 7-core multicore fiber. The error-free performance (BER<10 -9 ) for all the connections confirms that the proposed architecture can meet the existing demands in data centers and accommodate the future traffic growth.Index Terms-Data center networks, optical switching, space division multiplexing, wavelength division multiplexing, time division multiplexing. This work was supported by the ECFP7 grant no. 619572, COSIGN and Innovations Fonden grant 0603-00514B, E-SPACE. We would like to thank OFS for fabricating and providing the spliced fan-in/fan-out multicore fiber and Polatis for providing the 48x48 beam-steering fiber switch.

POTORI: A Passive Optical Top-of-Rack Interconnect Architecture for Data Centers

“…At the access tier each ToR switch is connected to a single ROADM. Space division multiplexing (SDM) is also considered in alloptical DCN solutions, e.g., [15] [16] for improving capacity. In [15], four architectures based on SDM are proposed, and it is shown that these architectures are suitable to apply in different DCs depending on their size and work load.…”

“…By replacing EPSs with optical switches, the reduced power-demanding electrical-to-optical (E/O) and optical-to-electrical (O/E) conversion is expected to dramatically decrease the power consumption of data center networks [8]. Several optical interconnect architectures for DCs are proposed in literature in recent years, e.g., [13]- [16]. These architectures employ all-optical switches based on different topologies and technologies at aggregation/core layer, but rely on conventional EPSs at ToR to interconnect servers in the racks.…”

Synchronization in a Random Length Ring Network for SDN-Controlled Optical TDM Switching

“…However, the need for extra components, ultimately leading to higher component cost and additional control overhead has shown to be detrimental for the lack of deployment. In order to provide support for optical subwavelength switching while at the same time avoiding the need for optical buffering in the network, we have previously proposed the concept of optical TDM switching [2,3]. Comparing optical TDM switching against OPS and OBS, the main difference lays in the nature of the connections.…”

“…The main network scenario for optical subwavelength switching in this work is intra data center network, based on the architecture proposed in [2,3] where the optical TDM switches are connected in a ring. The focus is therefore on the synchronization requirements for such a network.…”

“…For these reasons, optical DCN architectures have been proposed on several occasions. In [2,3] we proposed time division multiplexed (TDM) circuit switching in the optical domain to be deployed as one of the switching dimensions of multidimensional switching nodes connected in a ring topology. The main motivation behind the use of optical TDM is the ability to accommodate bursty traffic by using a single wavelength shared among different connections, thus providing better resource utilization.…”