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Jean Myoupo

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Papers by Jean Myoupo

Deployment of Sparse Sensor-Actuator Network in a Virtual Architecture

The use of a virtual architecture in wireless sensor networks provides a powerful and fast partit... more The use of a virtual architecture in wireless sensor networks provides a powerful and fast partitioning into a set of clusters, each being locatable in space by the sink or base station (BS for short). We first propose a protocol for the detection of empty clusters due to poor distribution of sensors or in low-density network. After this detection, we propose a strategy to allow mobile sensors (actuators) to move to position themselves on empty clusters in order to improve the routing of collected data. Key Works: Wireless Sensor-Actuator Networks, Virtual Architecture.

Secure and Energy-efficient Geocast Protocols for Wireless Sensor Networks based on a Hierarchical Clustered Structure

WoS-CoMS : Work Stealing-based Congestion Management Scheme for SDN programmable networks

In recent years, the SDN (Software-Defined Networking) paradigm emerged as an easy way to manage ... more In recent years, the SDN (Software-Defined Networking) paradigm emerged as an easy way to manage large-scale network infrastructures through programmability brought out and its control plane/data plane decoupling logic. This enables infrastructure and service providers to have a global view of the network and track traffic flows from a remote controller. However, congestion control remains a concern due to the evolution of increasingly complex and resource-intensive user requirements (virtual reality, metaverse, Internet of Things (IoT), Artificial Intelligence (AI), Cloud, ...) on network infrastructures. This server state leads to high latency in request processing and data loss. This paper proposes in such controller-supervised environment, a congestion management scheme within network service servers to maintain acceptable quality of service. The strategy relies on work stealing to ensure better workload balancing. Simulations show that the proposed solution can reduce congestio...

Speeding up Coarse Grain Multicomputer Based Parallel Algorithm for Optimal Binary Search Tree by Minimizing Idleness of Processors

2017 IEEE 19th International Conference on High Performance Computing and Communications; IEEE 15th International Conference on Smart City; IEEE 3rd International Conference on Data Science and Systems (HPCC/SmartCity/DSS)

This paper revisits a former work on a CGM-based parallel algorithm for Optimal Binary Search Tre... more This paper revisits a former work on a CGM-based parallel algorithm for Optimal Binary Search Tree problem. It was shown that, using Knuth sequential algorithm, this CGM algorithm requires O(p1/2) communication rounds and O(n2/p) local computations per processor. Where n is the size of the problem and p is the number of processors used. However this former algorithm leads to high idleness of processors due to the non-efficient communication protocol used. Here we improve the communication protocol in order to minimize idleness of processors and consequently improve the execution time. The simulation results show that the time of execution can be improved up to 44% when p<= 20.

A coarse-grained multicomputer parallel algorithm for the sequential substring constrained longest common subsequence problem

Parallel Computing

Four-Splitting Based Coarse-Grained Multicomputer Parallel Algorithm for the Optimal Binary Search Tree Problem

SSRN Electronic Journal, 2022

Coarse-Grained Multicomputer Based-Parallel Algorithms for the Longest Common Subsequence Problem with a String-Exclusion Constraint

2018 International Conference on High Performance Computing & Simulation (HPCS), 2018

In this paper, new parallel algorithms based on the Coarse-Grained Multicomputer (CGM) model for ... more In this paper, new parallel algorithms based on the Coarse-Grained Multicomputer (CGM) model for solving the Longest Common Subsequence (LCS) problem with a string exclusion constraint (STR-EC-LCS) is presented. Based on a previous sequential algorithm, we propose two CGM parallel algorithms for STR-EC-LCS problem. We perform an experimental study of our two solutions to validate our theoretical predictions, and conclude that our first algorithm that minimizes idleness of the processors is better than the second. To the best of our knowledge, these algorithms are the first CGM- based parallel algorithms for the generalized-constrained-LCS problem.

A Centralized and Conflict-Free Routing Table Update Method through Triplets' Lists Vector in SDN Architectures

2018 IEEE SmartWorld, Ubiquitous Intelligence & Computing, Advanced & Trusted Computing, Scalable Computing & Communications, Cloud & Big Data Computing, Internet of People and Smart City Innovation (SmartWorld/SCALCOM/UIC/ATC/CBDCom/IOP/SCI), 2018

For a long time, the distributed management protocols have proven their efficiency in managing co... more For a long time, the distributed management protocols have proven their efficiency in managing computers' networks; however, the recent success of centralized management architectures such as software-defined networking (SDN) to supervise large-scale network infrastructures such as the Cloud, is attracting increasing interest from major computer network companies. In this architecture type, the network switches and routers just simply forward packets by following the flow table rules set by a controller, which owns the control plane of the network. Thus, faced with a failure, for example, the concerned nodes follow the rules provided by the same controller. With the IPFRR (IP Fast ReRoute) routing strategy known for its fast rerouting capabilities, these rules are computed and set up in the devices in advance. However, when a link or node failure becomes persistent over time, the controller must recompute the routing paths and update the nodes in order to keep an acceptable qual...

A fast sequential algorithm for the matrix chain ordering problem

Concurrency and Computation: Practice and Experience, 2021

SummaryThis article presents a fast sequential algorithm for the matrix chain ordering problem. O... more SummaryThis article presents a fast sequential algorithm for the matrix chain ordering problem. Our solution is based on Yao's sequential algorithm that solves this problem in time by reducing the total number of distinct subproblems to be performed. We solve them fastly by avoiding some unnecessary computations. Our strategy consists in organizing the evaluation of the subproblems according to their dependencies instead of their precedence order as in the previous solutions. In many cases, our solution runs in time. An experimental study is conducted to benchmark the performance of our algorithm by measuring the average of the results obtained on five random data sets. This shows that our algorithm is 18.93 faster than Yao's sequential algorithm and 5.07 faster than the previous best CGM‐based parallel solutions on 32 processors.

A dominant point-based parallel algorithm that finds all longest common subsequences for a constrained-MLCS problem

Journal of Computational Science, 2020

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Efficient CGM-based parallel algorithms for the longest common subsequence problem with multiple substring-exclusion constraints

Parallel Computing, 2019

Fault-tolerant and energy-efficient routing protocols for a virtual three-dimensional wireless sensor network

Computers & Electrical Engineering, 2018

Load Balancing Schemes for Parallel Processing of Dynamic Programming on BSP/CGM Model

Parallel and Distributed Processing Techniques and Applications, 2010

International audienceno abstrac

Cliques and clusters based hierarchical scheme for sensor networks partitioning

2013 7th IEEE GCC Conference and Exhibition (GCC), 2013

ABSTRACT The hierarchical clustering for wireless sensors networks is treated to solve the scalab... more ABSTRACT The hierarchical clustering for wireless sensors networks is treated to solve the scalability problem in routing protocols for multi-hop wireless networks. Also a clustering-based technique is proposed to provide location management of devices for QoS support. To the best of our knowledge there is no protocol that combines the hierarchical partitioning into clusters and cliques taking into account the size of cliques and clusters (a clique is a network where every node can communicate directly with every other node in the same clique). In this paper, we propose a new partitioning scheme motivated by the need to have minimum and maximum size for cliques and clusters. In fact, this size has a direct effect on energy consumption. Indeed, for a large size of clique or cluster the cluster head should register the identities of its cluster members and manage them. That is not always feasible because sensor networks have a very limited memory capacity and energy. In addition, limiting the number of sensors in each clique or cluster avoids a significant number of cluster head re-election where the energy will be the parameter of election. So the characteristics of WSN are not satisfied, the aim of our work is to deal with these cases.

A Partial Sorting Algorithm in Multi-Hop Wireless Sensor Networks

The partial sorting problem is to sort the k smallest elements of a given set of n integers such ... more The partial sorting problem is to sort the k smallest elements of a given set of n integers such that 1 <k <n in descending order. The algorithms that exist in the literature for the partial sorting in wireless networking solutions are based on single-hop model. In this paper we consider a multi_hop sensor network. Initially, we partition the network into several levels by using the method of Gerla and Tsai. We consider that each node has a data item and two linked lists. Once the network is partitioned with multiple levels, each cluster runs the algorithm MaxCluster seeking the maximum element in that cluster. Then the algorithm Partial_Sorting finds separators (separators are identified by the algorithm MaxCluster) and helps to identify the remaining elements of the list to be sorted. We give the upper bound of our algorithm in terms of broadcast rounds. We also extend our approach to the case where each node has multiple data items instead of a single datum. Finally Experim...

A Conflict-Free Routing Tables Update Method for Persistent Multilink and Node Failures in SDN Architectures

Journal of Computer Science, 2019

The large-scale network management abilities of centralized architectures, such as Software-Defin... more The large-scale network management abilities of centralized architectures, such as Software-Defined Networking (SDN), are attracting increasing interest from major computer networking companies. In this architecture type, the nodes follow the rerouting rules predefined by the control plane in the controller. However, when a link or node failure becomes persistent over the time, the controller must recompute the routing and rerouting rules and update the relevant nodes to maintain an acceptable quality of service (QoS). In this study, we propose a conflict-free mechanism for updates of routing and rerouting tables of nodes by the controller. This mechanism works without disrupting the current traffic if both persistent multilink and node failures occur. We describe an efficient strategy for choosing the nodes to update and define an update scheme for these nodes. We show through the simulations of our updating scheme on various networks that our strategy improves QoS by reducing packet routing delays and the data loss rate in case of persistent multilink and node failures in the network. We also compare our results to those of several existing studies.

FSB-DReViSeR: Flow Splitting-Based Dynamic Replacement of Virtual Service Resources for Mobile Users in Virtual Heterogeneous Networks

Journal of Computer Networks and Communications, 2020

Virtual networks are sets of virtual devices that are interconnected through a physical network t... more Virtual networks are sets of virtual devices that are interconnected through a physical network to provide services to end users. These services are usually heterogeneous (VOIP, VoD, streaming, etc.), exploit various amounts of resources (bandwidth, computing power, servers, etc.), and have topologies different from those of the substrate network. These variations in requirements are traditionally known as the architectural flexibility of virtual networks. Each virtual service is provided through a server called a virtual service resource. When a virtual service resource can no longer provide a good quality of service to end users due to the traffic variation generated by their mobility, two approaches are commonly implemented: provisioning the virtual network with resources or replacing the virtual service resource by migrating the service to another node that offers the most suitable amount of resource to satisfy the quality of service (QoS). In this paper, we propose a flow split...

Conflict-free rerouting scheme through flow splitting for virtual networks using switches

Journal of Internet Services and Applications, 2018

The weaknesses of the Internet led to the creation of a new network paradigmnetwork virtualizatio... more The weaknesses of the Internet led to the creation of a new network paradigmnetwork virtualization. Virtualization is a very successful technique for sharing and reusing resources, which results in higher efficiency. Despite its advantages, including flexibility in network architecture, virtualization imposes many challenges, such as physical resource allocation to virtual devices. An efficient allocation strategy for these resources can ensure good Quality of Service (QoS) in virtual networks, whether in node or link failure events. This paper presents a conflict-free rerouting scheme with efficient additional capacity usage for link and node failure resilience in a virtual network using switches. Combining an IP Fast Rerouting approach and flow-splitting strategy, this scheme provides short reaction time, stable performance and low complexity because the rerouting calculation and configuration are performed in advance. We show that rerouting by traffic splitting based on the entering arc and destination is sufficient to address all link-failure situations in the network, assuming that the network is two-link connected. After modelling the dimensioning problem as an Integer Linear Programme, we demonstrate through practical implementation of our rerouting scheme on different networks that the scheme can substantially minimize the additional capacity draw on the substrate network. A solution using multiple virtual planes is also provided to solve several conflict problems in the case of simultaneous multiple link failures.

High Performance CGM-based Parallel Algorithms for the Optimal Binary Search Tree Problem

International Journal of Grid and High Performance Computing, 2016

In this paper, the authors highlight the existence of close relations between the execution time,... more In this paper, the authors highlight the existence of close relations between the execution time, efficiency and number of communication rounds in a family of CGM-based parallel algorithms for the optimal binary search tree problem (OBST). In this case, these three parameters cannot be simultaneously improved. The family of CGM (Coarse Grained Multicomputer) algorithms they derive is based on Knuth's sequential solution running in time and space, where n is the size of the problem. These CGM algorithms use p processors, each with local memory. In general, the authors show that each algorithms runs in with communications rounds. is the granularity of their model, and is a parameter that depends on and . The special case of yields a load-balanced CGM-based parallel algorithm with communication rounds and execution steps. Alternately, if , they obtain another algorithm with better execution time, say , the absence of any load-balancing and communication rounds, i.e., not better tha...

Deriving CGM Based-Parallel Algorithms for the Optimal Binary Search-Tree Problem

Advances in Intelligent Systems and Computing, 2016

This paper presents a methodology to derive CGM (Coarse Grain Multicomputer) parallel algorithms ... more This paper presents a methodology to derive CGM (Coarse Grain Multicomputer) parallel algorithms for the cost of the Optimal Binary Search Tree Problem (OBST Problem). Depending on the parameter we want to optimize, we derive an algorithm accordingly. Therefore a load balancing, an efficient and a minimum communication rounds algorithms are obtained. Our CGM algorithms use p processors, each with O(n 2 /p) local memory. The best one in communication requires O(p 1/2 ) communication rounds and O(n 2 /p) computations on each processor. Another one with the best time efficiency needs only O(n 2 /p) time steps. All local computations on processors are based on the Knuth sequential algorithm for the OBST problem.

Deployment of Sparse Sensor-Actuator Network in a Virtual Architecture

The use of a virtual architecture in wireless sensor networks provides a powerful and fast partit... more The use of a virtual architecture in wireless sensor networks provides a powerful and fast partitioning into a set of clusters, each being locatable in space by the sink or base station (BS for short). We first propose a protocol for the detection of empty clusters due to poor distribution of sensors or in low-density network. After this detection, we propose a strategy to allow mobile sensors (actuators) to move to position themselves on empty clusters in order to improve the routing of collected data. Key Works: Wireless Sensor-Actuator Networks, Virtual Architecture.

Secure and Energy-efficient Geocast Protocols for Wireless Sensor Networks based on a Hierarchical Clustered Structure

WoS-CoMS : Work Stealing-based Congestion Management Scheme for SDN programmable networks

In recent years, the SDN (Software-Defined Networking) paradigm emerged as an easy way to manage ... more In recent years, the SDN (Software-Defined Networking) paradigm emerged as an easy way to manage large-scale network infrastructures through programmability brought out and its control plane/data plane decoupling logic. This enables infrastructure and service providers to have a global view of the network and track traffic flows from a remote controller. However, congestion control remains a concern due to the evolution of increasingly complex and resource-intensive user requirements (virtual reality, metaverse, Internet of Things (IoT), Artificial Intelligence (AI), Cloud, ...) on network infrastructures. This server state leads to high latency in request processing and data loss. This paper proposes in such controller-supervised environment, a congestion management scheme within network service servers to maintain acceptable quality of service. The strategy relies on work stealing to ensure better workload balancing. Simulations show that the proposed solution can reduce congestio...

Speeding up Coarse Grain Multicomputer Based Parallel Algorithm for Optimal Binary Search Tree by Minimizing Idleness of Processors

2017 IEEE 19th International Conference on High Performance Computing and Communications; IEEE 15th International Conference on Smart City; IEEE 3rd International Conference on Data Science and Systems (HPCC/SmartCity/DSS)

This paper revisits a former work on a CGM-based parallel algorithm for Optimal Binary Search Tre... more This paper revisits a former work on a CGM-based parallel algorithm for Optimal Binary Search Tree problem. It was shown that, using Knuth sequential algorithm, this CGM algorithm requires O(p1/2) communication rounds and O(n2/p) local computations per processor. Where n is the size of the problem and p is the number of processors used. However this former algorithm leads to high idleness of processors due to the non-efficient communication protocol used. Here we improve the communication protocol in order to minimize idleness of processors and consequently improve the execution time. The simulation results show that the time of execution can be improved up to 44% when p<= 20.

A coarse-grained multicomputer parallel algorithm for the sequential substring constrained longest common subsequence problem

Parallel Computing

Four-Splitting Based Coarse-Grained Multicomputer Parallel Algorithm for the Optimal Binary Search Tree Problem

SSRN Electronic Journal, 2022

Coarse-Grained Multicomputer Based-Parallel Algorithms for the Longest Common Subsequence Problem with a String-Exclusion Constraint

2018 International Conference on High Performance Computing & Simulation (HPCS), 2018

In this paper, new parallel algorithms based on the Coarse-Grained Multicomputer (CGM) model for ... more In this paper, new parallel algorithms based on the Coarse-Grained Multicomputer (CGM) model for solving the Longest Common Subsequence (LCS) problem with a string exclusion constraint (STR-EC-LCS) is presented. Based on a previous sequential algorithm, we propose two CGM parallel algorithms for STR-EC-LCS problem. We perform an experimental study of our two solutions to validate our theoretical predictions, and conclude that our first algorithm that minimizes idleness of the processors is better than the second. To the best of our knowledge, these algorithms are the first CGM- based parallel algorithms for the generalized-constrained-LCS problem.

A Centralized and Conflict-Free Routing Table Update Method through Triplets' Lists Vector in SDN Architectures

2018 IEEE SmartWorld, Ubiquitous Intelligence & Computing, Advanced & Trusted Computing, Scalable Computing & Communications, Cloud & Big Data Computing, Internet of People and Smart City Innovation (SmartWorld/SCALCOM/UIC/ATC/CBDCom/IOP/SCI), 2018

For a long time, the distributed management protocols have proven their efficiency in managing co... more For a long time, the distributed management protocols have proven their efficiency in managing computers' networks; however, the recent success of centralized management architectures such as software-defined networking (SDN) to supervise large-scale network infrastructures such as the Cloud, is attracting increasing interest from major computer network companies. In this architecture type, the network switches and routers just simply forward packets by following the flow table rules set by a controller, which owns the control plane of the network. Thus, faced with a failure, for example, the concerned nodes follow the rules provided by the same controller. With the IPFRR (IP Fast ReRoute) routing strategy known for its fast rerouting capabilities, these rules are computed and set up in the devices in advance. However, when a link or node failure becomes persistent over time, the controller must recompute the routing paths and update the nodes in order to keep an acceptable qual...

A fast sequential algorithm for the matrix chain ordering problem

Concurrency and Computation: Practice and Experience, 2021

SummaryThis article presents a fast sequential algorithm for the matrix chain ordering problem. O... more SummaryThis article presents a fast sequential algorithm for the matrix chain ordering problem. Our solution is based on Yao's sequential algorithm that solves this problem in time by reducing the total number of distinct subproblems to be performed. We solve them fastly by avoiding some unnecessary computations. Our strategy consists in organizing the evaluation of the subproblems according to their dependencies instead of their precedence order as in the previous solutions. In many cases, our solution runs in time. An experimental study is conducted to benchmark the performance of our algorithm by measuring the average of the results obtained on five random data sets. This shows that our algorithm is 18.93 faster than Yao's sequential algorithm and 5.07 faster than the previous best CGM‐based parallel solutions on 32 processors.

A dominant point-based parallel algorithm that finds all longest common subsequences for a constrained-MLCS problem

Journal of Computational Science, 2020

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Efficient CGM-based parallel algorithms for the longest common subsequence problem with multiple substring-exclusion constraints

Parallel Computing, 2019

Fault-tolerant and energy-efficient routing protocols for a virtual three-dimensional wireless sensor network

Computers & Electrical Engineering, 2018

Load Balancing Schemes for Parallel Processing of Dynamic Programming on BSP/CGM Model

Parallel and Distributed Processing Techniques and Applications, 2010

International audienceno abstrac

Cliques and clusters based hierarchical scheme for sensor networks partitioning

2013 7th IEEE GCC Conference and Exhibition (GCC), 2013

ABSTRACT The hierarchical clustering for wireless sensors networks is treated to solve the scalab... more ABSTRACT The hierarchical clustering for wireless sensors networks is treated to solve the scalability problem in routing protocols for multi-hop wireless networks. Also a clustering-based technique is proposed to provide location management of devices for QoS support. To the best of our knowledge there is no protocol that combines the hierarchical partitioning into clusters and cliques taking into account the size of cliques and clusters (a clique is a network where every node can communicate directly with every other node in the same clique). In this paper, we propose a new partitioning scheme motivated by the need to have minimum and maximum size for cliques and clusters. In fact, this size has a direct effect on energy consumption. Indeed, for a large size of clique or cluster the cluster head should register the identities of its cluster members and manage them. That is not always feasible because sensor networks have a very limited memory capacity and energy. In addition, limiting the number of sensors in each clique or cluster avoids a significant number of cluster head re-election where the energy will be the parameter of election. So the characteristics of WSN are not satisfied, the aim of our work is to deal with these cases.

A Partial Sorting Algorithm in Multi-Hop Wireless Sensor Networks

The partial sorting problem is to sort the k smallest elements of a given set of n integers such ... more The partial sorting problem is to sort the k smallest elements of a given set of n integers such that 1 <k <n in descending order. The algorithms that exist in the literature for the partial sorting in wireless networking solutions are based on single-hop model. In this paper we consider a multi_hop sensor network. Initially, we partition the network into several levels by using the method of Gerla and Tsai. We consider that each node has a data item and two linked lists. Once the network is partitioned with multiple levels, each cluster runs the algorithm MaxCluster seeking the maximum element in that cluster. Then the algorithm Partial_Sorting finds separators (separators are identified by the algorithm MaxCluster) and helps to identify the remaining elements of the list to be sorted. We give the upper bound of our algorithm in terms of broadcast rounds. We also extend our approach to the case where each node has multiple data items instead of a single datum. Finally Experim...

A Conflict-Free Routing Tables Update Method for Persistent Multilink and Node Failures in SDN Architectures

Journal of Computer Science, 2019

The large-scale network management abilities of centralized architectures, such as Software-Defin... more The large-scale network management abilities of centralized architectures, such as Software-Defined Networking (SDN), are attracting increasing interest from major computer networking companies. In this architecture type, the nodes follow the rerouting rules predefined by the control plane in the controller. However, when a link or node failure becomes persistent over the time, the controller must recompute the routing and rerouting rules and update the relevant nodes to maintain an acceptable quality of service (QoS). In this study, we propose a conflict-free mechanism for updates of routing and rerouting tables of nodes by the controller. This mechanism works without disrupting the current traffic if both persistent multilink and node failures occur. We describe an efficient strategy for choosing the nodes to update and define an update scheme for these nodes. We show through the simulations of our updating scheme on various networks that our strategy improves QoS by reducing packet routing delays and the data loss rate in case of persistent multilink and node failures in the network. We also compare our results to those of several existing studies.

FSB-DReViSeR: Flow Splitting-Based Dynamic Replacement of Virtual Service Resources for Mobile Users in Virtual Heterogeneous Networks

Journal of Computer Networks and Communications, 2020

Virtual networks are sets of virtual devices that are interconnected through a physical network t... more Virtual networks are sets of virtual devices that are interconnected through a physical network to provide services to end users. These services are usually heterogeneous (VOIP, VoD, streaming, etc.), exploit various amounts of resources (bandwidth, computing power, servers, etc.), and have topologies different from those of the substrate network. These variations in requirements are traditionally known as the architectural flexibility of virtual networks. Each virtual service is provided through a server called a virtual service resource. When a virtual service resource can no longer provide a good quality of service to end users due to the traffic variation generated by their mobility, two approaches are commonly implemented: provisioning the virtual network with resources or replacing the virtual service resource by migrating the service to another node that offers the most suitable amount of resource to satisfy the quality of service (QoS). In this paper, we propose a flow split...

Conflict-free rerouting scheme through flow splitting for virtual networks using switches

Journal of Internet Services and Applications, 2018

The weaknesses of the Internet led to the creation of a new network paradigmnetwork virtualizatio... more The weaknesses of the Internet led to the creation of a new network paradigmnetwork virtualization. Virtualization is a very successful technique for sharing and reusing resources, which results in higher efficiency. Despite its advantages, including flexibility in network architecture, virtualization imposes many challenges, such as physical resource allocation to virtual devices. An efficient allocation strategy for these resources can ensure good Quality of Service (QoS) in virtual networks, whether in node or link failure events. This paper presents a conflict-free rerouting scheme with efficient additional capacity usage for link and node failure resilience in a virtual network using switches. Combining an IP Fast Rerouting approach and flow-splitting strategy, this scheme provides short reaction time, stable performance and low complexity because the rerouting calculation and configuration are performed in advance. We show that rerouting by traffic splitting based on the entering arc and destination is sufficient to address all link-failure situations in the network, assuming that the network is two-link connected. After modelling the dimensioning problem as an Integer Linear Programme, we demonstrate through practical implementation of our rerouting scheme on different networks that the scheme can substantially minimize the additional capacity draw on the substrate network. A solution using multiple virtual planes is also provided to solve several conflict problems in the case of simultaneous multiple link failures.

High Performance CGM-based Parallel Algorithms for the Optimal Binary Search Tree Problem

International Journal of Grid and High Performance Computing, 2016

In this paper, the authors highlight the existence of close relations between the execution time,... more In this paper, the authors highlight the existence of close relations between the execution time, efficiency and number of communication rounds in a family of CGM-based parallel algorithms for the optimal binary search tree problem (OBST). In this case, these three parameters cannot be simultaneously improved. The family of CGM (Coarse Grained Multicomputer) algorithms they derive is based on Knuth's sequential solution running in time and space, where n is the size of the problem. These CGM algorithms use p processors, each with local memory. In general, the authors show that each algorithms runs in with communications rounds. is the granularity of their model, and is a parameter that depends on and . The special case of yields a load-balanced CGM-based parallel algorithm with communication rounds and execution steps. Alternately, if , they obtain another algorithm with better execution time, say , the absence of any load-balancing and communication rounds, i.e., not better tha...

Deriving CGM Based-Parallel Algorithms for the Optimal Binary Search-Tree Problem

Advances in Intelligent Systems and Computing, 2016

This paper presents a methodology to derive CGM (Coarse Grain Multicomputer) parallel algorithms ... more This paper presents a methodology to derive CGM (Coarse Grain Multicomputer) parallel algorithms for the cost of the Optimal Binary Search Tree Problem (OBST Problem). Depending on the parameter we want to optimize, we derive an algorithm accordingly. Therefore a load balancing, an efficient and a minimum communication rounds algorithms are obtained. Our CGM algorithms use p processors, each with O(n 2 /p) local memory. The best one in communication requires O(p 1/2 ) communication rounds and O(n 2 /p) computations on each processor. Another one with the best time efficiency needs only O(n 2 /p) time steps. All local computations on processors are based on the Knuth sequential algorithm for the OBST problem.