Some LCP Decompositions of Multistage Interconnection Networks

Some useful layered cross product decompositons are derived both for general bit permutation networks and for(2n-1)-stage multistage interconnection networks.Several issues in related works are clarified and the rearrangeability of some interesting networks are considered.In particular, the rearrangeability of one class of networks is formulated as a new type of combinatorial design problmes.

Panconnectivity for Interconnection Networks with Faulty Elements

Let Go and G1 be two graphs with the same vertices. The new graph G（G0, G1; M） is a graph with the vertex set V（0o） ∪）V（G1） and the edge set E（Go） UE（G1） UM, where M is an arbitrary perfect matching between the vertices of Go and G1, i.e., a set of cross edges with one endvertex in Go and the other endvertex in G1. In this paper, we will show that if Go and G1 are f-fault q-panconnected, then for any f 〉 2, G（G0, G1; M） is （f ＋ 1）-fault （q ＋ 2）-panconnected.

Fast Multicast on Multistage Interconnection Networks Using Multi-Head Worms

This paper proposes a new approach for implementing fast multicast on multistage interconnection networks (MINs) with multi-head worms. For an MIN with n stages of k×k switches, a single multi-head worm can cover an arbitrary set of destinations with a single communication start-up. Compared with schemes using unicast messages, this approach reduces multicast latency significantly and performs better than multi-destination worms.

A New Family of Interconnection Networks of Fixed Degree Three

A new family of interconnection networks WG_n is proposed, that is constantdegree 3 Cayley graph, and is isomorphic to a Cayley graph of the wreath product Z_2\S_n when thegenerator set is chosen properly. Its different algebraic properties is investigated and a routingalgorithm is given with the diameter upper bounded by 3n^2 - 6n + 4. The embedding properties andthe fault tolerance are devired. In conclusion, we present a comparison of some familiar networkswith constant degree 3.

A Kind of Multistage Interconnection Networks with Multiple Paths

Multistage Interconnection Networks (MINs) are often used to provide interconnections in multiprocessor systems. A unique path MIN usually has lower hardware complekity and a simple control algorithm, but it lacks fault tolerance.This paper proposes a kind of multipath MINs, which are obtained by adding auxiliary links at the final stage in Quad nee (QT) networks so that they canprovide more paths between each source-destination pair, and presents theirrouting algorithm which is both destination tag based and adaptive. Starting with the routing tag for the minimum path between a given source-destinationpair, the routing algorithm uses a set of rules to select switches and modifyrouting tag. In addition to trying the andliary link when linko and link1 areunavailable, link1 will be tried when link0 is unavailable. This feattire dis-tinguishing the proposed routing algorithm from that for QT networks makesbetter use of all the possible paths between the given source-destination pair.In the end, this paper introduces a performance index, which is called capacity,to compare different kinds of MINs. Comparison shows that the proposed MINshave better capacity than QT networks.

A General Approach to L(h,k)-Label Interconnection Networks

Given two non-negative integers h and k, an L（h, k）-labeling of a graph G = （V, E） is a function from the set V to a set of colors, such that adjacent nodes take colors at distance at least h, and nodes at distance 2 take colors at distance at least k. The aim of the L（h, k）-labeling problem is to minimize the greatest used color. Since the decisional version of this problem is NP-complete, it is important to investigate particular classes of graphs for which the problem can be efficiently solved. It is well known that the most common interconnection topologies, such as Butterfly-like, Beneg, CCC, Trivalent Cayley networks, are all characterized by a similar structure： they have nodes organized as a matrix and connections are divided into layers. So we naturally introduce a new class of graphs, called （l × n）-multistage graphs, containing the most common interconnection topologies, on which we study the L（h, k）-labeling. A general algorithm for L（h, k）-labeling these graphs is presented, and from this method an efficient L（2, 1）-labeling for Butterfly and CCC networks is derived. Finally we describe a possible generalization of our approach.

A Scalable Interconnection Scheme in Many-Core Systems

Recent architectures of multi-core systems may have a relatively large number of cores that typically ranges from tens to hundreds;therefore called many-core systems.Such systems require an efficient interconnection network that tries to address two major problems.First,the overhead of power and area cost and its effect on scalability.Second,high access latency is caused by multiple cores’simultaneous accesses of the same shared module.This paper presents an interconnection scheme called N-conjugate Shuffle Clusters(NCSC)based on multi-core multicluster architecture to reduce the overhead of the just mentioned problems.NCSC eliminated the need for router devices and their complexity and hence reduced the power and area costs.It also resigned and distributed the shared caches across the interconnection network to increase the ability for simultaneous access and hence reduce the access latency.For intra-cluster communication,Multi-port Content Addressable Memory(MPCAM)is used.The experimental results using four clusters and four cores each indicated that the average access latency for a write process is 1.14785±0.04532 ns which is nearly equal to the latency of a write operation in MPCAM.Moreover,it was demonstrated that the average read latency within a cluster is 1.26226±0.090591 ns and around 1.92738±0.139588 ns for read access between cores from different clusters.

Reliability Assessment of a New General Matching Composed Network

The reliability of a network is an important indicator for maintaining communication and ensuring its stable operation. Therefore, the assessment of reliability in underlying interconnection networks has become an increasingly important research issue. However, at present, the reliability assessment of many interconnected networks is not yet accurate,which inevitably weakens their fault tolerance and diagnostic capabilities. To improve network reliability,researchers have proposed various methods and strategies for precise assessment. This paper introduces a novel family of interconnection networks called general matching composed networks(gMCNs), which is based on the common characteristics of network topology structure. After analyzing the topological properties of gMCNs, we establish a relationship between super connectivity and conditional diagnosability of gMCNs. Furthermore, we assess the reliability of g MCNs, and determine the conditional diagnosability of many interconnection networks.

Reliability Analysis of Varietal Hypercube

Connectivity is a vital metric to explore fault tolerance and reliability of network structure based on a graph model. Let be a connected graph. A connected graph G is called supper-κ (resp. supper-λ) if every minimum vertex cut (edge cut) of G is the set of neighbors of some vertex in G. The g-component connectivity of a graph G, denoted by , is the minimum number of vertices whose removal from G results in a disconnected graph with at least g components or a graph with fewer than g vertices. The g-component edge connectivity can be defined similarly. In this paper, we determine the g-component (edge) connectivity of varietal hypercube for small g.

Diagnosabilities of exchanged hypercube networks under the pessimistic one-step diagnosis strategy

The exchanged hypercube EH（s, t） （where s ≥ 1 and t ≥ 1） is obtained by systematically reducing links from a regular hypercube Q,＋t＋l. One-step diagnosis of exchanged hypercubes which involves only one testing phase during which processors test each other is discussed. The diagnosabilities of exchanged hypercubes are studied by using the pessimistic one-step diagno- sis strategy under two kinds of diagnosis models： the PMC model and the MM model. The main results presented here are the two proofs that the degree of diagnosability of the EH（s, t） under pessimistic one-step tl/tl fault diagnosis strategy is 2s where I ≤ s ≤ t （respectively, 2t, where 1 ≤ t ≤ s） based on the PMC model and that it is also 2s where 1 ≤ s ≤ t （respectively, 2t, where 1 ≤ t ≤ s） based on the MM＊ model.

An Analytical Model for Torus Networks in the Presence of Batch Message Arrivals with Hot-spot Destinations

Interconnection networks are hardware fabrics supporting communications between individual processors in multi- computers. The low-dimensional k-ary n-cubes （or torus） with adaptive wormhole switching have attracted significant research efforts to construct high-performance interconnection networks in contemporary multi-computers. The arrival process and destination distribution of messages have great effects on network performance. With the aim of capturing the characteristics of the realistic traffic pattern and obtaining a deep understanding of the performance behaviour of interconneetion networks, this paper presents an analytical model to investigate the message latency in adaptive-routed wormhole-switched torus networks where there exists hot-spot nodes and the message arrivals follow a batch arrival process. Each generated message has a given probability to be directed to the hot-spot node. The average degree of virtual channel multiplexing is computed by the GE/G/1/V queueing system with finite buffer capacity. We compare analytical results of message latency with those obtained through the simulation experiments in order to validate the accuracy of the derived model.

Dynamic load balancing based on restricted multicast tree in triplet-based hierarchical interconnection network

To solve the load balancing problem in a triplet-based hierarchical interconnection network（THIN） system, a dynamic load balancing （DLB）algorithm--THINDLBA, which adopts multicast tree （MT）technology to improve the efficiency of interchanging load information, is presented. To support the algorithm, a complete set of DLB messages and a schema of maintaining DLB information in each processing node are designed. The load migration request messages from the heavily loaded node （HLN）are spread along an MT whose root is the HLN. And the lightly loaded nodes（LLNs） covered by the MT are the candidate destinations of load migration; the load information interchanged between the LLNs and the HLN can be transmitted along the MT. So the HLN can migrate excess loads out as many as possible during a one time execution of the THINDLBA, and its load state can be improved as quickly as possible. To avoid wrongly transmitted or redundant DLB messages due to MT overlapping, the MT construction is restricted in the design of the THINDLBA. Through experiments, the effectiveness of four DLB algorithms are compared, and the results show that the THINDLBA can effectively decrease the time costs of THIN systems in dealing with large scale computeintensive tasks more than others.

Development of Network Interconnection in China

This paper introduces the current situation of China power industry and interconnection, the necessity to develop interconnection, the principle of nationwide interconnection and the key technologies to be studiedinclude HVDC and FACTS. The paper also discusses thefeasibility of 750 kV to be used in the northwest.regionand to speed up research and development of nighervoltage level in other regions of China, as well as scl-ence and technical innovation for transmission and dis-tribution projects.

Research on reliability index of a large communication network with domain partition and interconnection

In order to indicate the performances of a large-scale communication network with domain partition and interconnection today, a kind of reliability index weighed by normalized capacity is defined. Based on the route rules of network with domain partition and interconnection, the interconnection indexes among the nodes within the domain and among the domains are given from several aspects. It is expatiated on that the index can thoroughly represent the effect on the reliability index of the objective factor and the subjective measures of the designer, which obeys the route rules of a network with domain partition and interconnection. It is discussed that the defined index is rational and compatible with the traditional index.

An Improved Interconnection Network Based on NIN

The Novel Interconnection Network (NIN) based on inverted-graph topology and crossbar switch is a kind of lower latency and higher throughput interconnection network. But it has a vital disadvantage, high hardware complexity. In order to reduce system hardware cost, an improved NIN (ININ) structure is proposed. As same as NIN, ININ has constant network diameter. Besides of keeping advantages of NIN, hardware cost of ININ is lower than NIN. Furthermore, we design a new deadlock-free routing algorithm for the improved NIN. Key words NIN - ININ - inverted-graph interconnection network - hardware complexity - network band-width - network throughput CLC number TP 302 Foundation item: Supported by the National Natural Science Foundation of China (69873016)Biography: Li Fei (1974-), male, Ph. D candidate, research direction: architecture of interconnection network.

An new representation for interconnection network structures

An important theoretic interest is to study the relations between different interconnection networks, and to compare the capability and performance of the network structures. The most popular way to do the investigation is network emulation. Based on the classical voltage graph theory, the authors develop a new representation scheme for interconnection network structures. The new approach is a combination of algebraic methods and combinatorial methods. The results demonstrate that the voltage graph theory is a powerful tool for representing well known interconnection networks and in implementing optimal network emulation algorithms, and in particular, show that all popular interconnection networks have very simple and intuitive representations under the new scheme. The new representation scheme also offers powerful tools for the study of network routings and emulations. For example, we present very simple constructions for optimal network emulations from the cube connected cycles networks to the butterfly networks, and from the butterfly networks to the hypercube networks. Compared with the most popular way of network emulation, this new scheme is intuitive and easy to realize, and easy to apply to other network structures.

Algorithm and Performance Analysis of Optical Multistage Interconnection Network

A sorting algorithm based on the Batcher' s algorithm is presented. An 8X8multistage interconnection network(MIN) is constructed. Applying wavelength division multiplexing(WDM) technology and integrating control mode, the designed network can realize non-blockingcommunication. The time delay of the MIN and the switches needed are also analyzed in theory, thededuced result conforms that the MIN designed previously is feasible. In the case of the samecommunication quality guaranteed, MIN uses the least switches and completes the communication moreefficiently.

A Sufficient Condition for Networks to be n-Neighbor d-Diagnosable under the Comparison Model

Diagnosability of multiprocessor systems is an important research topic.The system and an interconnection network have an underlying topology,which is usually presented by a graph.In 2012,Peng et al.proposed a metric for fault diagnosis of the graph,namely,the n-neighbor diagnosability that restrains every fault-free node to contain at least n fault-free neighbors.It is difficult to get the n-neighbor diagnosability of the graph from the definition of the n-neighbor diagnosability.Afterwards,some sufficient and necessary conditions are given.It is also difficult to find the n-neighbor diagnosability of the graph from those results.In this paper,we show some new sufficient conditions for the graph to be n-neighbor d-diagnosable under the MM*model.It improves the corresponding result of[Theoretical Computer Science 773(2019)107-114].