MCF-SMF Hybrid Low-Latency Circuit-Switched Optical Network for Disaggregated Data Centers

Abstract

This paper proposes and experimentally evaluates a fully developed novel architecture with purpose built low latency communication protocols for next generation disaggregated data centers (DDCs). In order to accommodate for capacity and latency needs of disaggregated IT elements (i.e. CPU, memory), this architecture makes use of a low latency and high capacity circuit switched optical network for interconnecting various endpoints, that are equipped with multi-channel Silicon photonic based integrated transceivers. In a move to further decrease the perceived latency between various disaggregated IT elements, this paper proposes a) a novel network topology, which cuts down the latency over the optical network by 34% while enhancing system scalability and b) channel bonding over multicore fiber (MCF) switched links to reduce head to tail latency and in turn increase sustained memory bandwidth for disaggregated remote memory. Furthermore, to reduce power consumption and enhance space efficiency, the integration of novel multi core fiber (MCF) based transceivers, fibers and optical switches are proposed and experimentally validated at the physical layer for this topology. It is shown that the integration of MCF based subsystems in this topology can bring about an improvement in energy efficiency of the optical switching layer which is above 60%. Finally, the performance of this proposed architecture and topology is evaluated experimentally at the application layer where the perceived memory throughput for accessing remote and local resources is measured and compared using electrical circuit and packet switching. The results also highlight a multi fold increase in application perceived memory throughput over the proposed DDC topology by utilization and bonding of multiple optical channels to interconnect disaggregated IT elements that can be carried over MCF links.

A Novel Decomposed Optical Architecture for Satellite Terrestrial Network Edge Computing

“…Compared with milliseconds switching time in an Optical Circuit Switch (OCS)based network in [21] and microseconds switching time in a micro-ring resonator-based network in [23], the implemented NOS-based decomposed computing prototype can achieve nanoseconds switching time (43.4 ns), while keeping a stable interconnect link with none packet loss. These assessment results demonstrate the superiority of the proposed optical decomposed computing network based on NOS with respect to existing works.…”

“…A Software-Defined Networking (SDN)-based orchestration plane is designed and experimentally implemented for a decomposed computing architecture in [19] with hybrid optical switches. Decomposed architectures based on optical switches were proposed and experimentally investigated in [20,21], exploiting high aggregation bandwidths and transparent switching; however, the high switching delay (milliseconds) of the optical switch technology cannot provide nanoseconds scale communication between processor and memory cubes. An optically connected memory architecture was demonstrated in [22,23] based on micro-ring resonator switches and the Aurora 64B/66B protocol, which achieved an optical switching time of hundreds of microseconds.…”

On the challenges of optical disaggregated data center networking for ML/AI applications

“…Due to the low latencies and high bit-rates that are required for hardware module to hardware module communications (up to several hundreds of Gb/s in the case of CPU-to-CPU or CPU-to-memory), high performance technologies are required. In this regard, optical network technologies are seen as prime candidates for the interconnection of the several hardware blades [6], [8]. Several optical switches as well as fiber links enable the interconnection within and between the multiple racks hosting the blades.…”

Enabling Technologies for Optical Data Center Networks: Spatial Division Multiplexing

“…Obviously, SDM transmission has a great potential to address capacity requirement for the DC disaggregation. In the recently proposed resource centric disaggregated data center architecture [112], the integration of MCF-based transceivers, fibers, and optical switches is experimentally validated. The results show the benefits of SDM in terms of capacity, power consumption, latency and space efficiency for interconnecting disaggregated IT elements.…”