HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific re... more HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.
Heterogeneous networks (HetNets) which include macrocells with short range small cells proved a b... more Heterogeneous networks (HetNets) which include macrocells with short range small cells proved a better coverage and higher user data rates compared to classical networks. Using the same spectrum as the macrocells, small cells would allow increased spatial reuse of bandwidth. In industrialized countries, the deployment of new small cells by another actor (tier) to cover the outage improves the service with a lower cost. In this paper, we investigate cell association issue in heterogeneous networks composed of small and macrocells operating in the same spectrum. In contrast to the related work, we consider that the small cells are a cellular network belonging to another tier. Hence, there is competitiveness between the two tiers in order to selfishly maximize the gain while respecting the User Equipment (UE) Quality of Service (QoS) requirements. We propose a model based on game theory in order to get the best distribution of user equipments among small and macro base stations.
Advances in web technologies and engineering book series, 2021
This chapter explores the security challenges of the drone ecosystem. Drones raise significant se... more This chapter explores the security challenges of the drone ecosystem. Drones raise significant security and safety concerns, both design-time and run-time (e.g., supply-chain, technical design, standardization). Two broad classes of threats are considered, on drones and using drones (e.g., to attack critical infrastructures or vehicles). They involve both professional and non-professional drones and lead to various types of attacks (e.g., IoT-type vulnerabilities, GPS spoofing, spying, kinetic attacks). Trade-offs involving hardware and software solutions to meet efficiency, resource limitations, and real-time constraints are notably hard to find. So far, protection solutions remain elementary compared to the impact of attacks. Advances in technologies, new use cases (e.g., enhancing network connectivity), and a regulatory framework to overcome existing barriers are decisive factors for sustainable drone security market growth.
The deployment of small cells is one of the technical solutions to meet the challenge of data tra... more The deployment of small cells is one of the technical solutions to meet the challenge of data traffic rise. It reduces the cost of radio access networks. The efficiency of this solution depends on the success of cell planning to mitigate the interference. This work aims to optimize the incremental cell planning scheme that considers a preliminary macro-cell network infrastructure and expands it with new small cells to enhance the coverage and the capacity. In order to reduce the cost of installing new small cells, we consider a crowd networking business model where the Mobile Network Operator retrieves sites to deploy small cells above. We formulate the small cells placement problem as an Integer Linear Programming. It aims to maximize the coverage, ensure the required capacity and mitigate the cross-tier interference. Since the problem is NP-hard with large number of sites, we propose an heuristic to select the optimal sites locations around each macro cell. We tested the proposed heuristic with different simulation scenarios. The proposed Sequential Deployment scenario is better in coverage uniformity among dense and non dense zones whilst the Dense Zones First ensures more optimized selected sites number with better capacity in the dense zones in terms of users. The last scenario proves that higher candidate sites optimize the number of small cells in the non dense areas without compromising the coverage.
HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific re... more HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.
Industrial Partners (IPs) with Mobile Network Operators (MNOs) are extending the mobile network i... more Industrial Partners (IPs) with Mobile Network Operators (MNOs) are extending the mobile network infrastructure with Small Cells (SCs) in order to meet the growing mobile traffic demand. Due to the increasing number of telecommunication market competitors and the scarcity of radio resources, static sharing schemes are no more efficient. New dynamic schemes should be considered to meet both user expectations and economic success. In a crowd networking context, we propose in this work a dynamic radio resource scheme based on combinatorial double auctions. The participants in these auctions are the MNOs considered as buyers and the IPs, providers of SCs, considered as sellers. The commodity is a bundle of radio resources geographically distributed in several sites. This market place is regulated by an auctioneer responsible of pricing process and market clearing. The auctions are launched periodically to increase the elasticity. Theoretical analysis shows that this model satisfies the most important properties of auctions namely, strong balanced budget, individual rationality, incentive compatibility and economic efficiency. The proposed auction model is also simulated to evaluate the social welfare, the utilization percentage of the supplied resources and the service rate of the buyers demand. Results show that this model ensures a positive utility values for both sides with a service rate that exceeds 50\% and an utilization rate that reaches 50\% for some IPs.
This paper presents a proposal for incorporating a group communication paradigm into an object-ba... more This paper presents a proposal for incorporating a group communication paradigm into an object-based environment. Group communication is an interaction involving an arbitrary number of participants. Its application simpli es speci cation and implementation of complex systems. Object-oriented programming can signi cantly pro t from the addition of a group mechanism. Our proposed mechanism, Multiple Object Invocation, provides group communication among objects. The paper rst presents a model of general structure of group services and the use of group communication in this model. Multiple Object Invocation is presented and its characteristics and application in the general model is discussed. Implementation of Multiple Object Invocation in the Emerald object-oriented language and distributed operating system is presented.
2018 7th International Conference on Computer and Communication Engineering (ICCCE), 2018
Energy efficiency of radio access communication systems is an important aspect of the 5G communic... more Energy efficiency of radio access communication systems is an important aspect of the 5G communication framework as defined in the IMT2020 specifications. In this paper we study game theoretic approaches for minimizing the energy consumption of radio access networks using terminal cooperation. The strategies for energy efficient transmissions through relay based communications (terminals cooperating with each other) is presented and compared against a centralized approach. Simulations are conducted to show the performance variations in the energy efficiency of the considered strategies.
2021 International Wireless Communications and Mobile Computing (IWCMC)
Strong spatial relationships exist between call volume and human activities. In this paper, we sh... more Strong spatial relationships exist between call volume and human activities. In this paper, we show machine learning models can classify base station coverage areas into classes of mobile call profile based on areas geographic and demographic properties. We propose the novel approach of taking clustered Call Detail Records (CDR) based time series as ground truth, and passing heterogeneous features as inputs. These features were land use and points of interest retrieved from OpenStreetMap database, and demographic data provided Facebook Research. Together, they allowed the creation of a representation of urban fabric. CDR clusters were then characterized by these features through SHAP model interpretation. Three models were tested in the region of Dakar with CDR coming from D4D-Senegal Challenge. Results exceeded the accuracy of systematic most common class classification and the accuracy of models trained only on population dataset. Additionally, models generalization capacity were evaluated in Thies, with results equalling those of the baseline.
Wireless Mobile Applications and Services on WLAN Hotspots, 2006
Wireless LAN (WLAN) is rapidly growing as a popular technology for ubiquitous communication, wher... more Wireless LAN (WLAN) is rapidly growing as a popular technology for ubiquitous communication, where Internet access is being a standard commodity. The growing demand in WLAN technological development is to provide high quality and secure Internet access to mobile users using their portable devices. Nevertheless, WLAN is still restrictive, as it requires the presence of mobile users in the communication
The wireless industry is preparing the fifth generation wireless systems with several requirement... more The wireless industry is preparing the fifth generation wireless systems with several requirements regarding capacity and coverage area. A promising solution to meet this challenge is a densification of the network via a large scale deployment of small cells from different sizes. The advantage here is that small cells are easy to deploy and cost-efficient compared to macro base stations. However, the challenge is to ensure a reliable backhaul links. Mesh routers backhauling is one of the candidate solutions here, since it is easy to deploy, doesn't use wired connections between locations and cost-efficient. Nevertheless, the issue is to deploy routers in the suitable locations that provide the convenient and cheaper power sources. In this paper, we address the problem of mesh routers placement to ensure small cells backhauling. We propose a novel approach that aims to minimize the number of mesh routers and optimize their placement among locations offering the possibility to use solar panels. We first model the problem as an Integer Linear Program (ILP) and since it is hard to find the optimal solution with a large number of mesh routers and small cells, we propose also an heuristic approach called GPMR (Green Placement for Mesh Routers). We study the performance of both, the ILP model and the proposed heuristic GPMR, through simulations scenarios. Results show that GPMR provided performances close to those provided by ILP when the number of small cells is less than 10.We also show that the results provided by our heuristic GPMR follow an evolution close to the one observed in the optimal solutions when the number of small cells is high (more than 20).Thus, our heuristic approach can be used to obtain a near-optimal performance for ultra-dense networks.
The tradition network sharing models on existing mobile architecture is a challenging for the mob... more The tradition network sharing models on existing mobile architecture is a challenging for the mobile operator to cope the future competitive market while increasing average revenue per user. In fact, to sustain the future data tsunami, the operators are already investing in their network. However, they are not yet capturing their investments. The average revenue per user has declined. Moreover, the static and rapid commoditization of network equipments and service provisioning are pushing the mobile operators’ to adopt different strategies such as networking sharing in the access and core network for to reduce OPEX and CAPEX. In this paper, we proposed new models for mobile operators to share their network through cloud platform (e.g. pay-as-you-go) in order to open new business strategies and to reduce CAPEX and OPEX. On the other hand, this proposal also cops the future data tsunami and introduces more flexibility, elasticity and on-demand features to the LTE/EPC architecture.
Ce dispositif (20) permet d'identifier au moins une route satisfaisant au moins une premiere ... more Ce dispositif (20) permet d'identifier au moins une route satisfaisant au moins une premiere contrainte entre un nœud source et un nœud destinataire dans un reseau de telecommunications. Il comporte : des moyens (31, 32, 33) de mise en œuvre d'un protocole de routage proactif (PRP) apte a etablir une table de routage (TR) et une table de topologie (TT); des moyens (31, 32, 33) de test, agences pour verifier si une route entre le nœud source S et le nœud destinataire D determinee a partir de la table de routage (TR) verifie ladite au moins une premiere contrainte; des moyens (31, 32, 33) de selection d'un nombre predetermine (k) de routes potentielles (Rk) a partir de ladite table de topologie (TT); et des moyens (31, 32, 33) de recherche, agences pour rechercher au moins une route (R) parmi lesdites routes potentielles (Rk) satisfaisant ladite au moins une premiere contrainte.
To check a message (MES) to be transmitted by a sender attached to a sender domain (EXP) from a t... more To check a message (MES) to be transmitted by a sender attached to a sender domain (EXP) from a terminal connected to a transmitter domain (EM) to at least one recipient linked to an addressee domain (DES) the emitter domain requires authentication of the sender of the message by the sender domain. In response to a first request transmitted from the transmitter domain, the addressee domain transmits a second request to the sender domain to which rebroadcasts the field emitter if data previously transmitted by the sender domain to the domain of transmitter are identical to the data contained in the second query. The transmitter domain transmits a recipient domain response so that the latter receives the message from the sending domain and retransmit to a recipient who have agreed to receive the message.
Logically centralized network control design enables the separation of data-plane and control-pla... more Logically centralized network control design enables the separation of data-plane and control-plane in communication networks. Until today, there has not been a formal model to effectively investigate the resilience of such design. Therefore, here we model the problem of placing controllers in SDNs, given any network topology, so as to maximize the resilience of such networks. We begin with formal model definitions to optimize the most optimal controller placement locations. Based on the model, new ILP formulations have been defined. Subsequently, a simple but efficient greedy based heuristics has been proposed to solve the ILP. Performances are quantitatively evaluated and our results show significant reliability improvements in a given topology within the bounds of convergence delay.
2014 IEEE 15th International Conference on High Performance Switching and Routing (HPSR), 2014
Logically centralized network control design enables data-plane and control-plane separation in c... more Logically centralized network control design enables data-plane and control-plane separation in communication networks. Until today, traditional fault restoration mechanisms based on such designs were restricted to 'one' centralized network manager to detect faults and manually reroute traffic around effected areas. Nonetheless, this design is challenged by the overall scalability, restoration latency and convergence delay of the physically centralized controller. As a result, in this paper we argue that one can do a far more efficient network design. Here we propose, model, and design the problem of placing multiple centralized controllers, among multiple network topologies, so as to maximize the resilience and scalability of such networks-within the bounds of convergence delay. We begin with formal model definitions to optimize the controller placement locations. Based on the model, new ILP formulations have been defined. Subsequently, a simple but efficient greedy based heuristics has been proposed to solve the ILP. Performances are quantitatively evaluated and our results show significant reliability improvements in a given topology.
HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific re... more HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.
Heterogeneous networks (HetNets) which include macrocells with short range small cells proved a b... more Heterogeneous networks (HetNets) which include macrocells with short range small cells proved a better coverage and higher user data rates compared to classical networks. Using the same spectrum as the macrocells, small cells would allow increased spatial reuse of bandwidth. In industrialized countries, the deployment of new small cells by another actor (tier) to cover the outage improves the service with a lower cost. In this paper, we investigate cell association issue in heterogeneous networks composed of small and macrocells operating in the same spectrum. In contrast to the related work, we consider that the small cells are a cellular network belonging to another tier. Hence, there is competitiveness between the two tiers in order to selfishly maximize the gain while respecting the User Equipment (UE) Quality of Service (QoS) requirements. We propose a model based on game theory in order to get the best distribution of user equipments among small and macro base stations.
Advances in web technologies and engineering book series, 2021
This chapter explores the security challenges of the drone ecosystem. Drones raise significant se... more This chapter explores the security challenges of the drone ecosystem. Drones raise significant security and safety concerns, both design-time and run-time (e.g., supply-chain, technical design, standardization). Two broad classes of threats are considered, on drones and using drones (e.g., to attack critical infrastructures or vehicles). They involve both professional and non-professional drones and lead to various types of attacks (e.g., IoT-type vulnerabilities, GPS spoofing, spying, kinetic attacks). Trade-offs involving hardware and software solutions to meet efficiency, resource limitations, and real-time constraints are notably hard to find. So far, protection solutions remain elementary compared to the impact of attacks. Advances in technologies, new use cases (e.g., enhancing network connectivity), and a regulatory framework to overcome existing barriers are decisive factors for sustainable drone security market growth.
The deployment of small cells is one of the technical solutions to meet the challenge of data tra... more The deployment of small cells is one of the technical solutions to meet the challenge of data traffic rise. It reduces the cost of radio access networks. The efficiency of this solution depends on the success of cell planning to mitigate the interference. This work aims to optimize the incremental cell planning scheme that considers a preliminary macro-cell network infrastructure and expands it with new small cells to enhance the coverage and the capacity. In order to reduce the cost of installing new small cells, we consider a crowd networking business model where the Mobile Network Operator retrieves sites to deploy small cells above. We formulate the small cells placement problem as an Integer Linear Programming. It aims to maximize the coverage, ensure the required capacity and mitigate the cross-tier interference. Since the problem is NP-hard with large number of sites, we propose an heuristic to select the optimal sites locations around each macro cell. We tested the proposed heuristic with different simulation scenarios. The proposed Sequential Deployment scenario is better in coverage uniformity among dense and non dense zones whilst the Dense Zones First ensures more optimized selected sites number with better capacity in the dense zones in terms of users. The last scenario proves that higher candidate sites optimize the number of small cells in the non dense areas without compromising the coverage.
HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific re... more HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.
Industrial Partners (IPs) with Mobile Network Operators (MNOs) are extending the mobile network i... more Industrial Partners (IPs) with Mobile Network Operators (MNOs) are extending the mobile network infrastructure with Small Cells (SCs) in order to meet the growing mobile traffic demand. Due to the increasing number of telecommunication market competitors and the scarcity of radio resources, static sharing schemes are no more efficient. New dynamic schemes should be considered to meet both user expectations and economic success. In a crowd networking context, we propose in this work a dynamic radio resource scheme based on combinatorial double auctions. The participants in these auctions are the MNOs considered as buyers and the IPs, providers of SCs, considered as sellers. The commodity is a bundle of radio resources geographically distributed in several sites. This market place is regulated by an auctioneer responsible of pricing process and market clearing. The auctions are launched periodically to increase the elasticity. Theoretical analysis shows that this model satisfies the most important properties of auctions namely, strong balanced budget, individual rationality, incentive compatibility and economic efficiency. The proposed auction model is also simulated to evaluate the social welfare, the utilization percentage of the supplied resources and the service rate of the buyers demand. Results show that this model ensures a positive utility values for both sides with a service rate that exceeds 50\% and an utilization rate that reaches 50\% for some IPs.
This paper presents a proposal for incorporating a group communication paradigm into an object-ba... more This paper presents a proposal for incorporating a group communication paradigm into an object-based environment. Group communication is an interaction involving an arbitrary number of participants. Its application simpli es speci cation and implementation of complex systems. Object-oriented programming can signi cantly pro t from the addition of a group mechanism. Our proposed mechanism, Multiple Object Invocation, provides group communication among objects. The paper rst presents a model of general structure of group services and the use of group communication in this model. Multiple Object Invocation is presented and its characteristics and application in the general model is discussed. Implementation of Multiple Object Invocation in the Emerald object-oriented language and distributed operating system is presented.
2018 7th International Conference on Computer and Communication Engineering (ICCCE), 2018
Energy efficiency of radio access communication systems is an important aspect of the 5G communic... more Energy efficiency of radio access communication systems is an important aspect of the 5G communication framework as defined in the IMT2020 specifications. In this paper we study game theoretic approaches for minimizing the energy consumption of radio access networks using terminal cooperation. The strategies for energy efficient transmissions through relay based communications (terminals cooperating with each other) is presented and compared against a centralized approach. Simulations are conducted to show the performance variations in the energy efficiency of the considered strategies.
2021 International Wireless Communications and Mobile Computing (IWCMC)
Strong spatial relationships exist between call volume and human activities. In this paper, we sh... more Strong spatial relationships exist between call volume and human activities. In this paper, we show machine learning models can classify base station coverage areas into classes of mobile call profile based on areas geographic and demographic properties. We propose the novel approach of taking clustered Call Detail Records (CDR) based time series as ground truth, and passing heterogeneous features as inputs. These features were land use and points of interest retrieved from OpenStreetMap database, and demographic data provided Facebook Research. Together, they allowed the creation of a representation of urban fabric. CDR clusters were then characterized by these features through SHAP model interpretation. Three models were tested in the region of Dakar with CDR coming from D4D-Senegal Challenge. Results exceeded the accuracy of systematic most common class classification and the accuracy of models trained only on population dataset. Additionally, models generalization capacity were evaluated in Thies, with results equalling those of the baseline.
Wireless Mobile Applications and Services on WLAN Hotspots, 2006
Wireless LAN (WLAN) is rapidly growing as a popular technology for ubiquitous communication, wher... more Wireless LAN (WLAN) is rapidly growing as a popular technology for ubiquitous communication, where Internet access is being a standard commodity. The growing demand in WLAN technological development is to provide high quality and secure Internet access to mobile users using their portable devices. Nevertheless, WLAN is still restrictive, as it requires the presence of mobile users in the communication
The wireless industry is preparing the fifth generation wireless systems with several requirement... more The wireless industry is preparing the fifth generation wireless systems with several requirements regarding capacity and coverage area. A promising solution to meet this challenge is a densification of the network via a large scale deployment of small cells from different sizes. The advantage here is that small cells are easy to deploy and cost-efficient compared to macro base stations. However, the challenge is to ensure a reliable backhaul links. Mesh routers backhauling is one of the candidate solutions here, since it is easy to deploy, doesn't use wired connections between locations and cost-efficient. Nevertheless, the issue is to deploy routers in the suitable locations that provide the convenient and cheaper power sources. In this paper, we address the problem of mesh routers placement to ensure small cells backhauling. We propose a novel approach that aims to minimize the number of mesh routers and optimize their placement among locations offering the possibility to use solar panels. We first model the problem as an Integer Linear Program (ILP) and since it is hard to find the optimal solution with a large number of mesh routers and small cells, we propose also an heuristic approach called GPMR (Green Placement for Mesh Routers). We study the performance of both, the ILP model and the proposed heuristic GPMR, through simulations scenarios. Results show that GPMR provided performances close to those provided by ILP when the number of small cells is less than 10.We also show that the results provided by our heuristic GPMR follow an evolution close to the one observed in the optimal solutions when the number of small cells is high (more than 20).Thus, our heuristic approach can be used to obtain a near-optimal performance for ultra-dense networks.
The tradition network sharing models on existing mobile architecture is a challenging for the mob... more The tradition network sharing models on existing mobile architecture is a challenging for the mobile operator to cope the future competitive market while increasing average revenue per user. In fact, to sustain the future data tsunami, the operators are already investing in their network. However, they are not yet capturing their investments. The average revenue per user has declined. Moreover, the static and rapid commoditization of network equipments and service provisioning are pushing the mobile operators’ to adopt different strategies such as networking sharing in the access and core network for to reduce OPEX and CAPEX. In this paper, we proposed new models for mobile operators to share their network through cloud platform (e.g. pay-as-you-go) in order to open new business strategies and to reduce CAPEX and OPEX. On the other hand, this proposal also cops the future data tsunami and introduces more flexibility, elasticity and on-demand features to the LTE/EPC architecture.
Ce dispositif (20) permet d'identifier au moins une route satisfaisant au moins une premiere ... more Ce dispositif (20) permet d'identifier au moins une route satisfaisant au moins une premiere contrainte entre un nœud source et un nœud destinataire dans un reseau de telecommunications. Il comporte : des moyens (31, 32, 33) de mise en œuvre d'un protocole de routage proactif (PRP) apte a etablir une table de routage (TR) et une table de topologie (TT); des moyens (31, 32, 33) de test, agences pour verifier si une route entre le nœud source S et le nœud destinataire D determinee a partir de la table de routage (TR) verifie ladite au moins une premiere contrainte; des moyens (31, 32, 33) de selection d'un nombre predetermine (k) de routes potentielles (Rk) a partir de ladite table de topologie (TT); et des moyens (31, 32, 33) de recherche, agences pour rechercher au moins une route (R) parmi lesdites routes potentielles (Rk) satisfaisant ladite au moins une premiere contrainte.
To check a message (MES) to be transmitted by a sender attached to a sender domain (EXP) from a t... more To check a message (MES) to be transmitted by a sender attached to a sender domain (EXP) from a terminal connected to a transmitter domain (EM) to at least one recipient linked to an addressee domain (DES) the emitter domain requires authentication of the sender of the message by the sender domain. In response to a first request transmitted from the transmitter domain, the addressee domain transmits a second request to the sender domain to which rebroadcasts the field emitter if data previously transmitted by the sender domain to the domain of transmitter are identical to the data contained in the second query. The transmitter domain transmits a recipient domain response so that the latter receives the message from the sending domain and retransmit to a recipient who have agreed to receive the message.
Logically centralized network control design enables the separation of data-plane and control-pla... more Logically centralized network control design enables the separation of data-plane and control-plane in communication networks. Until today, there has not been a formal model to effectively investigate the resilience of such design. Therefore, here we model the problem of placing controllers in SDNs, given any network topology, so as to maximize the resilience of such networks. We begin with formal model definitions to optimize the most optimal controller placement locations. Based on the model, new ILP formulations have been defined. Subsequently, a simple but efficient greedy based heuristics has been proposed to solve the ILP. Performances are quantitatively evaluated and our results show significant reliability improvements in a given topology within the bounds of convergence delay.
2014 IEEE 15th International Conference on High Performance Switching and Routing (HPSR), 2014
Logically centralized network control design enables data-plane and control-plane separation in c... more Logically centralized network control design enables data-plane and control-plane separation in communication networks. Until today, traditional fault restoration mechanisms based on such designs were restricted to 'one' centralized network manager to detect faults and manually reroute traffic around effected areas. Nonetheless, this design is challenged by the overall scalability, restoration latency and convergence delay of the physically centralized controller. As a result, in this paper we argue that one can do a far more efficient network design. Here we propose, model, and design the problem of placing multiple centralized controllers, among multiple network topologies, so as to maximize the resilience and scalability of such networks-within the bounds of convergence delay. We begin with formal model definitions to optimize the controller placement locations. Based on the model, new ILP formulations have been defined. Subsequently, a simple but efficient greedy based heuristics has been proposed to solve the ILP. Performances are quantitatively evaluated and our results show significant reliability improvements in a given topology.
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Papers by Yvon Gourhant