The Data Vortex, an All Optical Path Multicomputer Interconnection Network

As power grids and optical interconnection networks are interdependent, the reliabilities of the optical networks are critical issues in power systems. The optical networks hold prominent performance including wide bandwidth, low loss, strong anti‐interference capability, high fidelity, and reliable performance. They are regarded as promising alternatives to electrical networks for parallel processing. This paper is aimed at taking the first step in understanding the communication efficiencies of optical networks. For that purpose, on optical networks, we propose a series of novel notions including communication pattern, r‐communication graph, reduced diameter, enhanced connectivity, r‐diameter, and r‐connectivity. Using these notions, we determine that the r‐diameter and r‐connectivity of the optical n‐dimensional hypercube network are ⌈n/r⌉ and , respectively. Since the parameter r is variable, we can adjust different values of r on the basis of the wavelength resources and load of the optical networks, achieving enhanced communication efficiencies of these networks. Compared with the electric n‐dimensional hypercube network, the proposed communication pattern on the optical hypercube network not only reduces the maximum communication delay of the conventional electrical hypercube significantly but also improves its fault tolerance remarkably.

Many different factors, such as topology, routing technique, selection function, flow control policy, complexity of router design, contribute to the performance of networks on chip (NoCs). Among these factors, the choice of topology and routing function has a significant effect on the average packet latency and saturation behavior. Torus is popular in many application domains, while the problem of virtual channel misbalance caused by its deadlock avoidance scheme brings lots of performance pathologies. In this paper, we present a novel deadlock avoidance scheme based on draining scheme, and propose a deadlock-free routing scheme for torus networks. We quantify the effects of the proposed routing scheme on the overall network performance by presenting simulation results for 1-D torus and 2-D torus NoCs. Experimental results show that the novel routing algorithm for torus networks could make more efficient use of virtual channel resources, and hence cutting down packet latency and boosting throughput. Note although this paper has considered 1-D and 2-D torus networks in the experimental evaluation, the new scheme is flexible enough to support highradix torus networks.

Analytical modeling techniques can be used to study the performance of optical multistage interconnection network (OMIN) effectively. MINs have assumed importance in recent times, because of their cost-effectiveness. An N?N MIN consists of a mapping from N processors to N memories, with log??2 N stages of 2?2 switches with N/2 switches per stage. The interest is on the study of the performance of unbuffered optical multistage interconnection network using the banyan network. The uniform reference model approach is assumed for the purpose of analysis. In this paper the analytical modeling approach is applied to an N?N OMIN with limited crosstalk (conflicts between messages) up to (log??2 N?1). Messages with switch conflicts satisfying the constraint of (log??2 N?1) are allowed to pass in the same group, but in case of a link conflict, the message is routed in a different group. The analysis is performed by calculating the bandwidth and throughput of the network operating under a load l and allowing random traffic and using a greedy routing strategy. A number of equations are derived using the theory of probability and the performance curves are plotted. The results obtained show that the performance of the network improves by allowing limited crosstalk in the network.

Analytical modeling techniques can be used to study the performance of optical multistage interconnection network (OMIN) effectively. MINs have assumed importance in recent times, because of their cost-effectiveness. An N/spl times/N MIN consists of a mapping from N processors to N memories, with log/sub 2/N stages of 2/spl times/2 switches with N/2 switches per stage. The interest is on the study of the performance of unbuffered optical multistage interconnection network using the Banyan network. The uniform reference model approach is assumed for the purpose of analysis. In this paper we apply the analytical modeling approach on an N/spl times/N OMIN with limited crosstalk (conflicts between messages) unto (log/sub 2/N-1). Messages with switch conflicts satisfying the constraint of (log/sub 2/N-1) are allowed to pass in the same group, but in case of a link conflict, than that message is routed in a different group. The analysis is performed by calculating the bandwidth of the network operating under a load l and allowing random traffic and using a greedy routing strategy. A number of equations are derived using the theory of probability and the performance curves are plotted. The results obtained show that the performance of the network improves by allowing limited crosstalk in the network.

Providing the optimal configuration for a software router poses a lot of technical challenges that do not present in the dedicated hardware router. One of them is how to characterize performance varying due to different configurations on commodity hardware. This paper addresses the problem of configuring a software router that provides the minimum of average packet latency. Since changing all combinations of hardware configurations of a software router for searching the optimum is cumbersome, we propose a prediction model to accurately estimate the packet latency of a software router. We first analyze the relationship of the packet latency distribution with the configured and observed parameters. Empirical measurements suggest that the Erlang-k distribution is a reasonable model for estimating the packet latency distribution. Motivated by the parameter relationship analysis, we propose a prediction model for packet latency of a software router based on the Erlang- k distribution. Our prediction model requires measurement of only two different configurations, i.e., one and two Rx queues of a network interface card, to predict the average packet latency of all combinations of configurations. We use the measured data from the testbed experiments and the data of curve fitting method to cross-verify the accuracy of our prediction model. Underlying the prediction model, we propose the optimal configuration selection (OCS) algorithm to justify which configuration yields the minimum of average packet latency. Our prediction model based OCS results in the same optimal configuration with the measured data based ones.

An optical interconnection architecture is proposed, which is based on optical ring and torus. The proposed optical interconnection network combines advantages of both ring and torus, e.g., simple node interface, constant node degree, better support for local communication and remote communication, wide bisection and good scalability etc. This architecture could be used to connect thousands of processing elements in massively parallel computer systems while maintaining a low latency and high bandwidth. The comparison with other popular networks is made, and the result shows that RTOIN (Ring based Torus Optical Interconnection Network) has pretty good node degree, network diameter, the number of links, bisection width and average message distance. Also, the result shows its excellent scalability, so it will probably be widely used in the area of parallel computing in future.

As applications scale to increasingly large processor counts, the interconnection network is frequently the limiting factor in application performance. In order to achieve application scalability, the interconnect must maintain high bandwidth while minimizing variation in packet latency. As the offered load in the network increases with growing problem sizes and processor counts, so does the expected maximum packet latency in the network, directly impacting performance of applications with any synchronized communication. Age-based packet arbitration reduces the variance in packet latency as well as average latency. This paper describes the Cray XT router packet aging algorithm which allows globally fair arbitration by incorporating age in the packet output arbitration. We describe the parameters of the aging algorithm and how to arrive at appropriate settings. We show that an efficient aging algorithm reduces both the average packet latency and the variance in packet latency on communication-intensive benchmarks.

Recent advances in photonics technologies have made optical interconnection network an attractive option for computing systems from high-performance computers and data centers to automobiles and cellphones. Optical interconnection network promises ultra-high bandwidth, low latency, and great energy efficiency to alleviate the inter-rack, intra-rack, intraboard, and intra-chip communication bottlenecks in multiprocessor systems. Silicon-based photonics technologies piggyback onto developed silicon fabrication processes to provide viable and cost-effective solutions. Both industry and academia have invested significant efforts to develop and commercialize optical interconnection network technologies. This paper reviews the latest progresses and provides insights into the challenges and future developments. © 2016 IEEE.

Routing with a (RC) is one of the most interesting techniques invented for improving the performance of routing techniques in IP networks by distributing the IP lookup process to all nodes along the path. The technique utilizes a small unit called clue to carry the IP lookup information onto the next node in the path. On the other hand, multiprotocol switching (MPLS) is claimed to be another routing technique over IP networks but employs a small unit called label to carry route information embedded in the packet from source to destination. In this paper, these two routing techniques over IP networks, namely, RC versus MPLS are investigated by using a simulation. Variable data rates are fluctuated into both networks ranging from 500 kbps up to 2.5 Mbps. Throughputs are collected under the same network environment. Mean queue length (MQL), mean waiting time (MWT), and network utilization (NU) are also measured in order to study how well both networks are able to manage the queue at the intermediate nodes, also how well both networks can utilize resources after the entering of packets. Simulation results are apparently proving that RC is far better than MPLS routing technique in terms of throughputs as well as queue management

In this paper we present a new architecture for building nonblocking optical multistage interconnection networks with a given size of building block. The maximum signal loss and crosstalk of this network are much less compared to those of the widely used crossbar network with a switch complexity of O(N/sup 2/). We have found that this architecture is a good choice for constructing nonblocking optical switch networks.

Transparent multihop optical networks suffer from the accumulation, from node to node, of intraband crosstalk and amplifier spontaneous emission noise, which may severely degrade the quality of the received signals. This paper presents a hybrid semi-transparent store-and-forward (H-S&F) node architecture which minimizes the number of hops and, therefore, significantly improves the quality of the signals. Cells are electronically stored in the case of conflict to avoid deflection, otherwise cells traverse the node without opto-electronic conversion. We present the teletraffic and transmission performance of regular two-connected networks in uniform traffic. Manhattan Street (MS) network and ShuffleNet (SN) are compared both analytically and by simulation. The H-S&F performs well, in terms of throughput, transit delay and BER. It is also shown that by combining deflection routing with the store and-forward scheme the network can accommodate two different bit-rates. This suggests that the proposed hybrid scheme may have a good potential for future multimedia networks.

While the large-scale Internet of Things (IoT) makes many new applications feasible, like Smart Cities, it also brings new concerns on data reliability, security, and privacy. The rapid evolution in blockchain technologies, which relied on a decentralized, immutable, and distributed ledger system for transaction data auditing, provides a prospective solution to address many issues for IoT security. The blockchain and smart contract enabled security mechanism for IoT applications have attracted increasing interests from both academia and industry. However, integrating cryptocurrency-oriented blockchain technologies into IoT systems meets tremendous challenges on scalability, storage capacity, security, and privacy. Particularly, the performance of blockchain networks significantly relies on the performance of consensus mechanisms, e.g., in terms of data confidentiality, transaction throughput, and network scalability. In this chapter, following an in-depth review of state-of-the-art blockchain networks, the key matrix of designing consensus mechanism for IoT networks are identified in terms of throughput, scalability, and security. To demonstrate a case study on designing scalable, lightweight blockchain protocols for IoT systems; a Microchain framework is introduced and a proof-of-concept prototype is implemented in a physical network environment. The experimental results verify the feasibility of integrating the Microchain into IoT systems.

Vertical stacking is a novel technique for creating nonblocking (crosstalk-free) optical multistage interconnection networks (MINs). In this paper, we propose a new class of optical MINs, the vertically stacked Benes (VSB) networks, for crosstalk-free realization of permutations in a single pass. An N x N VSB network requires at most O(N log N) switching elements, which is the same as the Benes network, and much lower overall hardware cost than that of the existing optical MINs built on the combination of horizontal expansion and vertical stacking of banyan networks, to provide the same crosstalk-free permutation capability. Furthermore, the structure of VSB networks provides a more flexible way for constructing optical MINs because they give more choices in terms of the number of stages used in an optical MIN. We also present efficient algorithms to realize crosstalk-free permutations in an N x N VSB network in time O(N log N), which matches the same bound as required by the reported schemes.

In this letter, we demonstrate a 2 times 2 switching node optimized for optical multistage interconnection networks. The optical packet-switched node is improved by making use of comparators with dual-threshold action to regenerate the routing header signal. The switching node is shown to correctly route packets with the presence of glitches in the header information. We employ a hybrid integrated semiconductor optical amplifier in the switching node that reduces packet guard times enabling a 67% increase in the number of stages for large-scale multistage networks.

In this paper, we study optical multistage interconnection networks (MINs). To increase the communication capability of parallel computing and reduce the communication latency of high-performance computing application, optical MINs represent a very important class of interconnecting schemes used for constructing optical interconnections for communication networks and multiprocessor systems. However, optical MINs still face their own challenges, e.g., cross-talk communication in optical interconnections which should be avoided to make them work properly. In this paper, we first analyze the properties of optical Cantor network and confliction conditions. Then, we show that any permutation is realizable under the constraint of avoiding cross-talk. Based on space domain approach, a routing scheme for realizing an all-to-all permutation by one pass in an optical Cantor network is also presented. Finally, we discuss the fault tolerance of this network.