Multi-ring Architecture Research Articles

The resilient hybrid fiber sensor network with self-healing function.

This paper presents a novel resilient fiber sensor network (FSN) with multi-ring architecture, which could interconnect various kinds of fiber sensors responsible for more than one measurands. We explain how the intelligent control system provides sensors with self-healing function meanwhile sensors are working properly, besides each fiber in FSN is under real-time monitoring. We explain the software process and emergency mechanism to respond failures or other circumstances. To improve the efficiency in the use of limited spectrum resources in some situations, we have two different structures to distribute the light sources rationally. Then, we propose a hybrid sensor working in FSN which is a combination of a distributed sensor and a FBG (Fiber Bragg Grating) array fused in a common fiber sensing temperature and vibrations simultaneously with neglectable crosstalk to each other. By making a failure to a working fiber in experiment, the feasibility and effectiveness of the network with a hybrid sensor has been demonstrated, hybrid sensors could not only work as designed but also survive from destructive failures with the help of resilient network and smart and quick self-healing actions. The network has improved the viability of the fiber sensors and diversity of measurands.

Planar Hall resistance ring sensor based on NiFe/Cu/IrMn trilayer structure

We have investigated the sensitivity of a planar Hall resistance sensor as a function of the ring radius in the trilayer structure Ta(3)/IrMn(10)/Cu(0.2)/NiFe(10)/Ta(3) (nm). The diagonal components of magnetoresistivity tensor in rectangular prism corresponding to anisotropic magnetoresistance are few ten times larger than that of off-diagonal component corresponding to planar Hall resistance. However, it is noteworthy that the resultant contribution is governed by the off-diagonal components due to the cancellation of diagonal components in the self-balanced bridge configuration. Both the experimental and theoretical results show that the sensitivity varies linearly with the ring radius. In multi-ring architecture, the circumference can be increased to a limit, which consequently enhances sensitivity. We found the sensitivity of the investigated 7-rings planar Hall to be more than 600 μV/Oe.

Impacts of Hierarchy in Ethernet Ring Networks on Service Resiliency

In transport networks, a multi-ring architecture is very useful to facilitate network planning and to design and provide more resilient services for customers. Unlike traditional synchronous optical network multi-rings, the service resiliency of Ethernet-based multi-rings is significantly impacted by the ring hierarchy because a link or node failure in a certain level ring triggers filtering database flush actions in all higher level rings as well as in the ring with the failure, and consequently a large amount of duplicated data frames may be flooded. In this paper, we investigate how the ring hierarchy impacts the service resiliency of multi-ring networks. Based on extensive experiments on various single- and multiple-link failures, we suggest two effective inter-ring connection rules to minimize the transient traffic and to ensure more resilient multi-ring networks. In addition, we consider a flush optimization technique called e-ADV, and show that the combination of e-ADV and multi-ring structures satisfying our inter-ring connection rules results in a more attractive survivability performance.

Impacts of Hierarchy in Ethernet Ring Networks on Service Resiliency

In transport networks, a multi-ring architecture is very useful to facilitate network planning and to design and provide more resilient services for customers. Unlike traditional synchronous optical network multi-rings, the service resiliency of Ethernet-based multi-rings is significantly impacted by the ring hierarchy because a link or node failure in a certain level ring triggers filtering database flush actions in all higher level rings as well as in the ring with the failure, and consequently a large amount of duplicated data frames may be flooded. In this paper, we investigate how the ring hierarchy impacts the service resiliency of multi-ring networks. Based on extensive experiments on various single- and multiple-link failures, we suggest two effective inter-ring connection rules to minimize the transient traffic and to ensure more resilient multi-ring networks. In addition, we consider a flush optimization technique called e-ADV, and show that the combination of e-ADV and multi-ring structures satisfying our inter-ring connection rules results in a more attractive survivability performance.

An input traffic allocation strategy and an efficient transmission technique for collisions-free WDM ring MANs

This paper presents a wavelength division multiplexing multi-ring architecture with a separate control wavelength for metropolitan area networks. We study the critical problem of low fiber bandwidth utilization that many access ring protocols introduce, especially at high load conditions. In our study this problem is effectively faced by: (1) applying an efficient slotted access algorithm to avoid both data wavelengths and receiver collisions, (2) introducing a number of buffers at each node to effectively allocate the incoming traffic into them, and (3) applying an efficient algorithm for buffer selection for transmission that combines the priority criteria of packet age and receiver collisions avoidance. In this way, we obtain maximum fiber bandwidth utilization. Especially, our aim is to achieve not only significant throughput enhancement, but also essential dropping probability and total delay reduction. Also, the number of transmission buffers per node is investigated in order to manage maximum throughput improvement, while considering the financial cost. Finally, a discrete-event simulation model based on Poisson statistics is developed for the performance measures evaluation.

Using mesh and multi-ring methods in the design of survivable wavelength-routed all-optical networks

This paper presents a comprehensive investigation of a wide range of protection strategies against all single link failures in all-optical wavelength division multiplexing (WDM) networks based on mesh and multi-ring architectures. In the mesh architecture, three protection strategies namely, minimal cost, single link basis and disjoint path protection strategies are investigated. In the multi-ring architecture, the distribution and non-distribution traffic multi-ring design strategies are extensively examined. Although, the concepts of mesh and multi-ring designs have previously been perceived to be fundamentally different, in this paper, we shall explain and show that these two architectures can be systematically related and viewed as a unified concept. This new way of looking at the fully survivable network design helps us to understand clearly the mechanisms and performance of each protection strategy. In addition, this approach allows us to see the trend of fiber-cost requirements that increase step-by-step from the most complicated mesh protection to the simplest multi-ring protection architectures. To minimize the system cost of 100% protection WDM networks, mathematical models based on the integer linear programming (ILP) are derived as the tool for achieving optimal path placement, wavelength assignment and ring selection simultaneously. Apart from the mathematical model, the main contributions of this paper are the analysis and comparison in aspects of the spare capacity requirement and ease of operation and practical feasibility amongst these protection strategies. However, the emphasis will be on the multi-ring protection schemes. In addition, the influence of the number of multiplexed wavelengths per fiber to design outcomes and the benefit of having wavelength conversion capability in WDM network environment are also studied. Copyright © 2004 AEI.

Design and Performance Evaluation of Traffic Grooming Algorithms in WDM Multi-Ring Networks

In this paper, we propose novel traffic grooming algorithms to reduce the cost of the entire system in WDM multi-ring networks. In order to achieve this goal, it is important to construct a virtual topology and groom the traffic in these networks. We consider four kinds of virtual topologies of WDM multi-ring networks according to the way in which traffic is transmitted among rings. Accordingly, we design four kinds of traffic grooming (TG) algorithms depending on the considered virtual topologies: mixed (MTG), partially mixed (PMTG), separate (STG), and independent (ITG) traffic grooming algorithms. Each algorithm consists of a separation, a connection-ring construction, and a grooming procedure. In the separation procedure, all traffic connections are classified into intra and inter-connections. The connection-ring construction procedure makes full connection-rings from traffic connections. The grooming procedure groups connection-rings onto a wavelength in order to reduce the number of SONET add/drop multiplexers (SADMs) and wavelengths and to improve the utilization of network resources. To analyze the performance of each algorithm, a circular multi-ring architecture with uniform traffic is considered. The simulation results show that ITG and PMTG are more efficient in terms of wavelengths. STG and PMTG require a smaller number of SADMs.

Design and analysis of a generalized multi-ring architecture

Design and analysis of a generalized multi-ring architecture

The REFINE multiprocessor — theoretical properties and algorithms

A reconfigurable interconnection network based on a multi-ring architecture called REFINE is described. REFINE embeds a single 1-factor of the Boolean hypercube in any given configuration. The mathematical properties of the REFINE topology and the hardware for the reconfiguration switch are described. The REFINE topology is scalable in the sense that the number of interprocessor communication links scales linearly with network size whereas the network diameter scales logarithmically with network size. Primitive parallel operations on the REFINE topology are described and analyzed. These primitive operations could be used as building blocks for more complex parallel algorithms. A large class of algorithms for the Boolean n-cube which includes the FFT and the Batcher's bitonic sort is shown to map efficiently on the REFINE topology. The REFINE multiprocessor is shown to offer a cost-effective alternative to the Boolean n-cube multiprocessor architecture without substantial loss in performance.

Exploiting instruction-level parallelism

The main challenge in the field of Very Large Instruction Word (VLIW) and superscalar architectures is ezploiting as much instruction-level parallelism as possible. In this paper an ezecution model which uses multiple instruction sequences and eztracts instruction-level parallelism at runtime from a set of enabled threads has been presented. A new multi-ring architecture has been proposed to support the ezeculion model. The multithreaded architecture features (i) large resident activations to improve program and data locality, (ii) a novel high-speed buger organization which ensures zero load/store stalls for the local variables of an activation, and (iii) a dynamic instruction scheduler that groups operations from multiple threads for ezecution. Initial performance evaluation studies predict that the proposed architecture is capable of ezecuting 7 concurrent operations per cycle with 8 ezecution pipes and 6 rings.

Token-ring local-area networks and their performance

The major technical concepts underlying token-ring technology are examined, and performance issues arising in the design of such local-area networks (LANs) are detailed. Following a survey of analytical queuing models to describe the basic token-ring operation, three topics are discussed in detail: (1) the IEEE 802.5 token ring and its performance; (2) the ANSI fiber distributed data interface (FDDI) token ring and its performance; and (3) architecture and performance issues arising in the interconnection of token-ring networks with regard to the various components of a multiring architecture demonstrating which congestion-control problems can arise in such a network and how they can be overcome. The author concludes with a number of open questions concerning the understanding of the quantitative behavior of token-ring-based LANs. >