Reliability Of Telecommunication Networks Research Articles

Analysis of the structural reliability of communication networks supporting protective switching mechanisms for one protected section and one backup section

Objectives. The service level agreement is an important tool used in building reasonable relations between subscribers and operators of telecommunication networks. This includes the quality of services provided. One key component is reliability as assessed by the availability factor. The most suitable model for assessing the reliability of the service provided is a random graph model based on the service contour. This is the set of technical resources involved in the provision of this service. In this formulation, the assessment of the reliability of the service is based on the reliability of elements which constitute the telecommunications network (graph), nodes (vertices) and communication lines (edges). At the same time, the availability factors of nodes and lines are determined by the design features of the distribution environment, as well as the technical means used to organize them. The purpose of this work is to develop an approach to analyzing the reliability of telecommunication networks which support protective switching mechanisms for one protected and one backup sections.Methods. The following methods are used: theory of random graphs, matrices, probabilities and computer modeling.Results. The elements of the route, both basic and reserving, are divided into three groups. The first indicates permanent unchangeable parts of the paths, the second group identifies the reserved sections, and the third group indicates the reserving sections. At the same time, each of the reserved and reserving sections is formed on the basis of specified preferences. They are usually aimed at increasing the resulting reliability, although other rules may be used. In the case of protective switching schemes for one protected section and one backup sections, a variant of forming routes used for further calculations of the reliability indicator is shown.Conclusions. Using the example of a backbone network, the study shows that the use of protective switching mechanisms for the case of one required transmission route demonstrates a significant increase in reliability, with the exception of the use of protective switching in sections. This is primarily due to the topology features of the network under consideration.

Holistic Resilience and Reliability Measures for Cellular Telecommunication Networks

Nowadays, our lives have become increasingly inseparable from the services facilitated by telecommunication networks. Disruption of this service may result in a significant detrimental effect, especially in smart manufacturing, remote surgery, and harbor logistic. With the development and deployment of the new generation of telecommunication, i.e., 5G mobile networks, reliability has been repeatedly emphasized as a critical issue. Contemporary telecommunication networks often have a large scale. Evaluating network reliability is a challenging issue related to the spatiotemporal characteristics of the network and of the connection principles. In this paper, we bring together concepts from computational geometry and reliability engineering to forge a new approach to address the challenging issue. We first formulate a Voronoi-based Graphic network (VGN) model with a novel built-in dependence, coverage dependence, that manifests the resilience of the network. Based on the VGN model, we propose two new measures for holistically assessing the resilience and reliability of telecommunication networks in a large region. Ultimately, we employ the designed approach to telecommunication networks. The result indicates that coverage dependence and resilience are important factors for delivering ultra-reliable service to users promised by the 5G.

Study of the Telecommunication Networks Performance and Reliability Indicators

It is currently urgent to improve the technical characteristics and increase the efficiency of telecommunication networks because of the global problem of ensuring the reliable transmission, processing and protection of commercial information in telecommunication networks. The aim of this study is to assess the reliability indicators of telecommunication networks and analyse the level of their development. The aim was achieved through the methods that were used to assess the reliability of the entire network: the generalized method of analytical assessment of the telecommunication network reliability; connection-based metrics; scaling of telecommunication networks, and application of unified reliability indicators to routine control, operation and maintenance. As a result of the research, the indicators of telecommunication networks were studied with and without using connection-based metrics. As a result, the network metrics were also divided into distribution and generation/transmission reliability and telecommunication network metrics – into connection-, performance-, and condition-based metrics, which showed improvements in network performance and reliability. As a prospect for further research, studying and improving the telecommunication network reliability indicators is suggested.

SFC Self-Modeling and Active Diagnosis

The 5G system should be flexible to cope with diversity of functions and infrastructure, in an efficient way while supporting a wide range of services associated with a set of requirements through Service Function Chaining (SFC). Fault management plays a paramount role to fulfill the SFC requirements towards reliability of telecommunication networks. Model-based (MB) approaches are knowledge-based systems that reason about a system from an explicit representation of its structure and functional behavior through a dependency model. MB techniques solve novel diagnosis problems and provide explanations for their decisions. However, current MB methods suffer from some limitations due to network virtualization challenges: lack of network visibility and dynamic topologies. To tackle those limitations, we propose a self-modeling approach and an active diagnosis process for virtual networks that considers two types of knowledge to build the model: acquired knowledge and learned knowledge provided by fault injection to expand and validate the proposed model. The experimental results from their application to a real-world virtual IP Multimedia Subsystem (vIMS) use case show that the self-modeling and the active diagnosis procedures are effective in determining the root cause(s) of a failure and explaining fault propagation.

Reducing the number of passing links in the 2D-NoC for performance and reliability improvement

Purpose The routing algorithm is one of the most important components in designing a network-on-chip (NoC). An effective routing algorithm can cause better performance and throughput, and thus, have less latency, lower power consumption and high reliability. Considering the high scalability in networks and fault occurrence on links, the more the packet reaches the destination (i.e. to cross the number of fewer links), the less the loss of packets and information would be. Accordingly, the proposed algorithm is based on reducing the number of passed links to reach the destination. Design/methodology/approach This paper presents a high-performance NoC that increases telecommunication network reliability by passing fewer links to destination. A large NoC is divided into small districts with central routers. In such a system, routing in large routes is performed through these central routers district by district. Findings By reducing the number of links, the number of routers also decreases. As a result, the power consumption is reduced, the performance of the NoC is improved, and the probability of collision with a faulty link and network latency is decreased. Originality/value The simulation is performed using the Noxim simulator because of its ability to manage and inject faults. The proposed algorithm, XY routing, as a conventional algorithm for the NoC, was simulated in a 14 × 14 network size, as the typical network size in the recent works.

ASSESSMENT OF THE STRUCTURAL RELIABILITY OF TELECOMMUNICATION NETWORKS OF UNCERTAIN TOPOLOGY BASED ON IMITATION MODELING

This article is devoted to the analysis of existing and the development of new approaches to assess the structural reliability of networks with an uncertain topology. Ensuring reliability in modern telecommunication networks is becoming an increasingly important issue in connection with the intensive development of these networks over the past decade. Existing structural methods for evaluating reliability are focused on applications for networks with a known structure. However, in cases where the network topology is constantly changing, these methods are of little use. Therefore, an approach is proposed for obtaining estimates of the structural reliability of telecommunication networks with an uncertain topology based on the use of basic structural characteristics alone. The developed method for assessing the reliability of telecommunication networks with an uncertain topology is presented, which provides the ability to determine: the total number of routes in the network with a certain number of nodes and branches; the number of routes per one connection, as well as the number of routes of rank no more than the allowable value that can be used for one connection. The upper limit of the structural reliability of individual connections are determined by the routes obtained for each connection), on the basis of which the structural reliability of a network with an uncertain topology is evaluated. A simulation computer model has been created for assessing the structural reliability of a telecommunication network with an uncertain topology, which consists of a computer model that empirically estimates the number of routes in various implementations of obtaining indicators of the structural reliability of communication between a pair of nodes and the entire network as a whole. A simulation experiment of computer modeling with given structural characteristics consists of a series of tests, in each of which a specific random implementation of a network graph is generated and all the routes existing in it are searched. The article presents the main functions and components of the developed software system, the figures show the modules and the basic algorithms of the model. Interfaces for inputting initial data and for outputting simulation results in the form of values ​​of the number of routes based on the results of simulation experiments and corresponding graphs are demonstrated. A separate important issue that is solved in the simulation is the determination of a sufficient number of tests in an experiment. The criterion for assessing this modeling parameter was the deviation dynamics of the average total number of routes of ranks 1 through 4 obtained in the tests.

Эксплуатационные показатели качества транспорт­ной телекоммуникационной первичной сети Украины

The paper presents statistical data on the number, nature and causes of the damage to underground fiber-optic communication lines, on which the transport telecommunication primary network is based, using an example of Donetsk and Lugansk regions for the period between 2001 and 2010. Comparison of these characteristics with the values of similar parameters over 2001—2005 allows to develop recommendations for the improvement of the reliability of telecommunication networks.

A Relationship between the Reliability of Telecommunication Networks and Electromagnetic Compatibility(<Special Survey>Communication Networks and the Human Society)

A Relationship between the Reliability of Telecommunication Networks and Electromagnetic Compatibility(<Special Survey>Communication Networks and the Human Society)

On maximal 3-restricted edge connectivity of regular graphs

Let G be a k-regular graph of order at least nine. It is proved in this work that graph G is maximally 3-restricted edge-connected if it is triangle-free and k>|G|/4+1, the lower bound on k is sharp to some extent. With this observation, we present an expression of the number of edge cuts in the previous graph, which may be employed to analyse the reliability of telecommunication networks.

Reliability, Availability and Cost Analysis of Large Multi-State Systems with Ageing Components

Reliability, Availability and Cost Analysis of Large Multi-State Systems with Ageing ComponentsBasic notions of the system multi-state reliability analysis are introduced. The multi-state series system with degrading components is defined and its exact reliability function is determined. The limit reliability function for large multi-state systems is introduced. An auxiliary theorem on limit reliability function of a large multi-state series system, which is necessary for its approximate reliability evaluation, is presented. On the basis of this auxiliary theorem some corollaries are formulated and proved and then applied to approximate reliability and availability determination of a large multi-state series system. Evaluations are given of a multi-state system reliability function, its mean lifetimes in the state subsets and their standard deviations, mean value and variance of the lifetime up to and the number of exceeding the system reliability critical state and its availability coefficient. The cost analysis of a multi-state series system is performed as well. The results are applied to a large telecommunication network reliability, availability and cost analysis.

Consideration of node failures in network-reliability calculation

Terminal-pair reliability is a common measure of telecommunication network reliability, and many algorithms for calculating it have been published. Most such algorithms presume perfect nodes; although some have presumed imperfect nodes. This paper presents a very simple, uncomplicated way to account for imperfect nodes.

Current Telecommunication Network Reliability Models: A Critical Assessment

This paper is a critique of major weaknesses of current techniques for analyzing the reliability of computer communication networks. Several of the most important factors influencing the reliability seen by users of such systems have been almost completely ignored or modeled in a rudimentary fashion. Ignoring such factors may be partially justified by the inherent complexity of the problems being studied, which often precludes exact computations being feasible for networks of any size, even with simplifying assumptions. Nevertheless, the results of models which ignore such factors are questionable even if they are computable. The focus of models of such networks should be on the effects of system malfunctions, degraded performance, excessive delays, etc., on system users. New approximate modeling techniques appear to be the most realistic approach to studying such problems.

An alternative index for the reliability of telecommunication networks : D. Trstensky and P. Bowron. IEEE Trans. Reliab.R-33 (4) 343 (October 1984)

A resonant multi-channel curve crossing problem is investigated by using the two-state semiclassical theory recently completed by the authors. The complex phase integral in the non-adiabatic tunneling type curve crossing is accurately replaced by the phase integral on the real axis. Thanks to this, the transition matrix propagation method based on the two-state theory can be applied to multi-state curve crossing problems without any restriction on the number of crossings and states. The present theory can handle even the case that the collision energy is lower than the highest avoided crossing. Numerical comparisons with the exact quantum results for a three-state problem demonstrate the excellence of the theory. Even the detailed feature of dense resonances is accurately reproduced. The theory does not require any complex calculus, any diabatization procedure nor any information on the couplings.

An Alternative Index for the Reliability of Telecommunication Networks

A new index for evaluating the reliability of telecommunication networks compares the effectiveness of the modelled actual system with that for an ideal (absolutely failureless) system. The new index is not only general, in that it takes account of all the states and the number of channels between vertices, but the procedure for its calculation allows more consistent choice of the special indexes of reliability. Some previous indexes can be derived from this as special cases.

Some thoughts on the reliability of telecommunication networks : H. Baczko. Telecommunication J.14, 729 (1974)

Some thoughts on the reliability of telecommunication networks : H. Baczko. Telecommunication J.14, 729 (1974)