Switching functions of a data center Top-of-Rack (ToR)

IEEE Network, 2000

ata centers (DCs) are currently the largest closedloop systems in the information technology (IT) and networking worlds, continuously growing toward multi-million-node clouds . DC operators manage and control converged IT and network infrastructures in order to offer a broad range of services and applications to their customers. Typical services and applications provided by current DCs range from traditional IT resource outsourcing (storage, remote desktop, disaster recovery, etc.) to a plethora of web applications (e.g., browsers, social networks, online gaming). Innovative applications and services are also gaining momentum to the point that they will become main representatives of future DC workloads. Among them, we can find high-performance computing (HPC) and big data applications . HPC encompasses a broad set of computationally intensive scientific applications, aiming to solve highly complex problems in the areas of quantum mechanics, molecular modeling, oil and gas exploration, and so on. Big data applications target the analysis of massive amounts of data collected from people on the Internet to analyze and predict their behavior.

2010

The basic building block of ever larger data centers has shifted from a rack to a modular container with hundreds or even thousands of servers. Delivering scalable bandwidth among such containers is a challenge. A number of recent efforts promise full bisection bandwidth between all servers, though with significant cost, complexity, and power consumption. We present Helios, a hybrid electrical/optical switch architecture that can deliver significant reductions in the number of switching elements, cabling, cost, and power consumption relative to recently proposed data center network architectures. We explore architectural trade offs and challenges associated with realizing these benefits through the evaluation of a fully functional Helios prototype.

Optical Switching in Next Generation Data Centers, 2018

This thesis presents advanced optical connectivity solutions for next-generation data centers, spanning millions of processing cores. The wavelength routing of optical packets based on arrayed waveguide gratings (AWGs), tunable wavelength converters (TWCs), and fiber delay lines (FDLs) is a disruptive technology for capacity, footprint, and flexibility requirements of massive cloud data centers. We develop

Journal of Optical Communications and Networking

Cloud services are fundamentally supported by data center networks (DCNs). With the fast growth of cloud services, the scale of DCNs is increasing rapidly, leading to great concern about system scalability due to multiple constraints. This paper proposes a scalable DCN architecture based on optical switching and transmission, with the distributed placement of optical switches and server racks at different nodes in a given optical network. This solves the scalability issue by relaxing power and cooling constraints and by reducing the number of (electronic) switches using high-capacity optical switches, as well as by simplifying DCN internal connections using wavelengths in the optical network. Moreover, the distributed optical switches provide service access interfaces to meet demand within areas, and thus reduce the transmission cost of the external traffic. The major concern is the additional delay and cost for remote transmissions of the DCN internal traffic. To this end, we study...

Journal of Electrical and Computer Engineering, 2014

Current data centers networks rely on electronic switching and point-to-point interconnects. When considering future data center requirements, these solutions will raise issues in terms of flexibility, scalability, performance and energy consumption. For this reason several optical switched interconnects, which make use of optical switches and wavelength division multiplexing (WDM), have been recently proposed. However, the solutions proposed so far suffer from low flexibility and are not able to provide service differentiation. Furthermore, very few studies evaluate scalability and energy consumption and make extensive comparison with current data center networks. In this paper we introduce a novel data center network based on hybrid optical switching (HOS). HOS combines optical circuit, burst and packet switching on the same network. In this way different data center applications can be mapped to the optical transport mechanism that best suits to their traffic characteristics. Furthermore, the proposed HOS network achieves high transmission efficiency and reduced energy consumption by using two parallel optical switches; a slow and low power consuming switch for the transmission of circuits and long bursts, and a fast switch for the transmission of packets and short bursts. We consider the architectures of both a traditional data center network and the proposed HOS network and present a combined analytical and simulation approach for their performance and energy consumption evaluation. We demonstrate that the proposed HOS data center network achieves high performance and flexibility while considerably reducing the energy consumption of current solutions.

Microwave and Optical Technology Letters, 2018

In high performance data center networks, switching the data from source node to destination node needs a proper signal processing to decode the address bits and switch the data and to avoid contention. In this article, we propose the hardware design for switching the data from one node to other bi-directionally. The design is verified in an experimental test bed.

2015 IEEE 4th International Conference on Cloud Networking (CloudNet), 2015

We propose a novel, hybrid optical-electronic switched network architecture with flexible bandwidth provisioning for scaling the capacity of the upper tiers of next generation datacenter and high-performance computing (HPC) networks. The network combines transparent optical packet switches, based on Arrayed Waveguide Grating (AWG) routers, and a deflection routing scheme to alleviate packet buffering requirements in the optical domain. Through simulation studies we show that, coupled with a dynamic switch-port bandwidth provisioning and load balancing scheme, the network can maintain high performance under changing traffic loading.

2018 International Conference on Optical Network Design and Modeling (ONDM), 2018

The introduction of all-optical switching in data center interconnection networks (DCN) is key for addressing several of the shortcomings of state-of-the-art electronic switched solutions. Limitations in the port count and reconfiguration speed of optical switches, however, require novel DCN designs offering network scalability and dynamicity. We present the NEPHELE DCN which relies on hybrid electro-optical top-of rack (TOR) switches to interconnect servers over multi-wavelength all-optical rings. We described in detail the NEPHELE control cycle which follows the SDN paradigm. We evaluate the performance of NEPHELE regarding the effect of the control plane delay under realistic traffic.

IEEE Access

Today, data center networks (DCNs) are built using multi-tier architecture. These large-scale networks face many challenges, such as security, delay, low throughput, loops, link oversubscription, TCP Incast and Outcast, etc. In this paper, a TCAM (Ternary Content Addressable Memory) based routing technique is proposed, augmenting the routing capabilities of multi-tier architectures in large scale networks. The routing complexities in these architectures are rectified and improved by implementing an additional TCAM based routing table in Leaf/ToR switches for a specific number of compute nodes in particular Pods, and it is scalable to whole datacenter nodes. To test the model, we implemented two prototype models: one depicting our proposed TCAM based switch and the other is a typical Top-of-the-Rack (ToR) switch and compared the performance of the proposed model and if any overhead introduced in it. The preliminary results show that our TCAM based routing table technique is fast and it forwards the network packets at line-rate, does not introduce considerable latency, on-chip resources power consumptions is less than 3%, and helps to solve or mitigate the above critical problems that are present in the current large DC's three-tier architecture, especially in Top of the Rack and aggregation layers switches. INDEX TERMS Data center networks, TCAM tables, top of the rack switches, link oversubscription, TCP incast and outcast, loops.

Proceedings of the 2013 18th European Conference on Network and Optical Communications & 2013 8th Conference on Optical Cabling and Infrastructure (NOC-OC&I), 2013

Current data centers (DCs) networks rely on electronic switching and point-to-point interconnects. When considering future DC requirements, point-to-point interconnects will lead to poor network scalability and large power consumption. For this reason several optical switched interconnects for DCs have been recently proposed. However, the proposed optical switching solutions suffer from low flexibility and are not able to provide service differentiation. Furthermore, very few studies evaluate possible improvements in energy efficiency offered by optical switching solutions. In this paper we introduce a novel architecture of interconnects for DCs based on hybrid optical switching (HOS). HOS combines three different optical switching paradigms, namely circuit, burst and packet switching within the same network. Furthermore, HOS envisages the use a two parallel optical switches, a slow and low power consuming switch for the transmission of data using circuits and long bursts, and a fast switch for the transmission of packets and short bursts. The possibility of choosing between circuits, bursts and packets ensures the flexibility required by future DCs. At the same time, the option to select the most suitable switch technology for each data flow guarantees high transmission efficiency and low power consumption.