Pub Date : 2018-06-01DOI: 10.1109/NETSOFT.2018.8460068
Q. Duan
Service function chaining (SFC) in the SDN/NFV architecture offers a flexible approach to end-to-end service provisioning in future networks. Analysis on the quality of service (QoS) guaranteed by SFC becomes an important research topic. The resource abstraction and dynamic elastic service provisioning enabled by SDN/NFV bring in new challenges to SFC performance evaluation that have not been fully addressed by existing approaches. In order to face such challenges, a novel modeling and analysis method is proposed in this paper for evaluating end-to-end service performance of SFC in the SDN/NFV architecture. Application of network calculus-based techniques in this paper makes the proposed modeling and analysis method agnostic to VNF implementations and adaptive to service capacity scaling; thus applicable to performance evaluation of SFC in SDN/NFV for dynamic elastic service provisioning.
{"title":"Modeling and Performance Analysis for Service Function Chaining in the SDN/NFV Architecture","authors":"Q. Duan","doi":"10.1109/NETSOFT.2018.8460068","DOIUrl":"https://doi.org/10.1109/NETSOFT.2018.8460068","url":null,"abstract":"Service function chaining (SFC) in the SDN/NFV architecture offers a flexible approach to end-to-end service provisioning in future networks. Analysis on the quality of service (QoS) guaranteed by SFC becomes an important research topic. The resource abstraction and dynamic elastic service provisioning enabled by SDN/NFV bring in new challenges to SFC performance evaluation that have not been fully addressed by existing approaches. In order to face such challenges, a novel modeling and analysis method is proposed in this paper for evaluating end-to-end service performance of SFC in the SDN/NFV architecture. Application of network calculus-based techniques in this paper makes the proposed modeling and analysis method agnostic to VNF implementations and adaptive to service capacity scaling; thus applicable to performance evaluation of SFC in SDN/NFV for dynamic elastic service provisioning.","PeriodicalId":333377,"journal":{"name":"2018 4th IEEE Conference on Network Softwarization and Workshops (NetSoft)","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122847722","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-06-01DOI: 10.1109/NETSOFT.2018.8459933
Flavio Esposito, F. Paganelli, R. Fantacci
Edge computing is an emerging paradigm whose goal is to boost with cloud resources available at the edge the computational capability of otherwise weak devices. This paradigm is mostly attractive to reduce user perceived latency. A central mechanism in edge computing is cyber-foraging, i.e., the search and delegation to capable edge cloud processes of tasks too complex, time consuming or resource intensive to be running on user devices or low-latency demanding to be running remotely, as a form of edge function. An edge function is any network or device-specific process that may be run on an edge process instead. Despite the recent interest for this technology from industry and academia, cyber-foraging techniques and protocols have yet to be standardized. In this paper, we leverage decomposition theory to propose an architecture providing insights in the design and implementation of protocols for cyber-foraging of multiple edge functions. In contrast with several existing solutions, we argue that the (distributed) cyber-foraging orchestration should be policy-based and not an ad-hoc solution, i.e., either a pure edge cloud burden or a device decision. To this end, via simulations, we show how our approach can be used by edge computing providers and application programmers to compare and evaluate different alternative cyber-foraging solutions. Our decomposition-based approach has general applicability to other network utility maximization problems, even outside the edge computing domain.
{"title":"A Decomposition-based Architecture for Distributed Cyber-Foraging of Multiple Edge Functions","authors":"Flavio Esposito, F. Paganelli, R. Fantacci","doi":"10.1109/NETSOFT.2018.8459933","DOIUrl":"https://doi.org/10.1109/NETSOFT.2018.8459933","url":null,"abstract":"Edge computing is an emerging paradigm whose goal is to boost with cloud resources available at the edge the computational capability of otherwise weak devices. This paradigm is mostly attractive to reduce user perceived latency. A central mechanism in edge computing is cyber-foraging, i.e., the search and delegation to capable edge cloud processes of tasks too complex, time consuming or resource intensive to be running on user devices or low-latency demanding to be running remotely, as a form of edge function. An edge function is any network or device-specific process that may be run on an edge process instead. Despite the recent interest for this technology from industry and academia, cyber-foraging techniques and protocols have yet to be standardized. In this paper, we leverage decomposition theory to propose an architecture providing insights in the design and implementation of protocols for cyber-foraging of multiple edge functions. In contrast with several existing solutions, we argue that the (distributed) cyber-foraging orchestration should be policy-based and not an ad-hoc solution, i.e., either a pure edge cloud burden or a device decision. To this end, via simulations, we show how our approach can be used by edge computing providers and application programmers to compare and evaluate different alternative cyber-foraging solutions. Our decomposition-based approach has general applicability to other network utility maximization problems, even outside the edge computing domain.","PeriodicalId":333377,"journal":{"name":"2018 4th IEEE Conference on Network Softwarization and Workshops (NetSoft)","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127288174","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-06-01DOI: 10.1109/NETSOFT.2018.8460099
José Manuel Sánchez-Vílchez, D. Sarmiento
Software-Defined Networking logically centralizes the intelligence inside the SDN controller, therefore the fault tolerance of an SDN not only depends on the SDN controller availability but also on its timely forwarding decisions in realtime to circumvent faults on the data plane. In this paper we compare the behavior of the opensource SDN controllers OpenDaylight and ONOS when circumventing faults on the data plane and dealing with topological changes to ensure the continuity of service. We evaluated both controllers under a set of fault scenarios conceived to deploy fully customizable network topologies by keeping a better configuration control on the interconnections than the existing in current simulation tools such as Mininet.
{"title":"Fault Tolerance Comparison of ONOS and OpenDaylight SDN Controllers","authors":"José Manuel Sánchez-Vílchez, D. Sarmiento","doi":"10.1109/NETSOFT.2018.8460099","DOIUrl":"https://doi.org/10.1109/NETSOFT.2018.8460099","url":null,"abstract":"Software-Defined Networking logically centralizes the intelligence inside the SDN controller, therefore the fault tolerance of an SDN not only depends on the SDN controller availability but also on its timely forwarding decisions in realtime to circumvent faults on the data plane. In this paper we compare the behavior of the opensource SDN controllers OpenDaylight and ONOS when circumventing faults on the data plane and dealing with topological changes to ensure the continuity of service. We evaluated both controllers under a set of fault scenarios conceived to deploy fully customizable network topologies by keeping a better configuration control on the interconnections than the existing in current simulation tools such as Mininet.","PeriodicalId":333377,"journal":{"name":"2018 4th IEEE Conference on Network Softwarization and Workshops (NetSoft)","volume":"227 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116428858","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-06-01DOI: 10.1109/NETSOFT.2018.8460100
J. Garay, J. Unzilla, E. Jacob, J. Matías
The need to support a wide variety of requirements, from the different verticals envisioned, make slicing a core component of the 5G scenario. One of the foundations of slicing is the capability of isolating the different services provided, to guarantee the required performance for each of them. The performance impact of the isolation mechanisms themselves becomes a key aspect that must be carefully balanced and evaluated in all the components of the infrastructure. In this paper, we introduce L2TSM, a Layer 2 Traffic Steering Mechanism for Network Slicing scenarios, including Service Function Chaining and Network Function Virtualization deployments. L2TSM minimizes the overhead, simplifies exposing the programmability of the network devices to be exploited by the service functions and maintains the isolation between the service chains, through a software-defined and standard compliant addressing scheme. With a case study in our L2TSM prototype, we show how different types of traffic composing a service chain are supported and gather some insights on the performance of the solution.
{"title":"A Layer 2 Traffic Steering Mechanism for Network Slicing scenarios","authors":"J. Garay, J. Unzilla, E. Jacob, J. Matías","doi":"10.1109/NETSOFT.2018.8460100","DOIUrl":"https://doi.org/10.1109/NETSOFT.2018.8460100","url":null,"abstract":"The need to support a wide variety of requirements, from the different verticals envisioned, make slicing a core component of the 5G scenario. One of the foundations of slicing is the capability of isolating the different services provided, to guarantee the required performance for each of them. The performance impact of the isolation mechanisms themselves becomes a key aspect that must be carefully balanced and evaluated in all the components of the infrastructure. In this paper, we introduce L2TSM, a Layer 2 Traffic Steering Mechanism for Network Slicing scenarios, including Service Function Chaining and Network Function Virtualization deployments. L2TSM minimizes the overhead, simplifies exposing the programmability of the network devices to be exploited by the service functions and maintains the isolation between the service chains, through a software-defined and standard compliant addressing scheme. With a case study in our L2TSM prototype, we show how different types of traffic composing a service chain are supported and gather some insights on the performance of the solution.","PeriodicalId":333377,"journal":{"name":"2018 4th IEEE Conference on Network Softwarization and Workshops (NetSoft)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129936518","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-06-01DOI: 10.1109/NETSOFT.2018.8460031
A. Pavlidis, Giannis Sotiropoulos, Kostas Giotis, D. Kalogeras, B. Maglaris
In this paper we propose a monitoring architecture based on dispersed vantage points in networking infrastructures. Our framework offers on-demand network monitoring data and related analytics to users and/or organizations, considered as tenants of shared infrastructures. Measurements are collected from monitoring agents scattered in a legacy production network, offering authorized users (tenants and administrators) better visibility of events. Adhering to the NFV principles we implemented, deployed and orchestrated management-plane monitoring and anomaly detection services using Docker containers. Thus, our architecture enables users to process, analyze and visualize customized network monitoring data. The proposed architecture was shown to be well-suited for anomaly detection schemas by considering measurements gathered from centralized and localized vantage points within a network.
{"title":"NFV-compliant Traffic Monitoring and Anomaly Detection based on Dispersed Vantage Points in Shared Network Infrastructures","authors":"A. Pavlidis, Giannis Sotiropoulos, Kostas Giotis, D. Kalogeras, B. Maglaris","doi":"10.1109/NETSOFT.2018.8460031","DOIUrl":"https://doi.org/10.1109/NETSOFT.2018.8460031","url":null,"abstract":"In this paper we propose a monitoring architecture based on dispersed vantage points in networking infrastructures. Our framework offers on-demand network monitoring data and related analytics to users and/or organizations, considered as tenants of shared infrastructures. Measurements are collected from monitoring agents scattered in a legacy production network, offering authorized users (tenants and administrators) better visibility of events. Adhering to the NFV principles we implemented, deployed and orchestrated management-plane monitoring and anomaly detection services using Docker containers. Thus, our architecture enables users to process, analyze and visualize customized network monitoring data. The proposed architecture was shown to be well-suited for anomaly detection schemas by considering measurements gathered from centralized and localized vantage points within a network.","PeriodicalId":333377,"journal":{"name":"2018 4th IEEE Conference on Network Softwarization and Workshops (NetSoft)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129715405","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-06-01DOI: 10.1109/NETSOFT.2018.8460073
M. Oplenskedal, P. Herrmann, J. Blech, Amirhosein Taherkordi
Modern Intelligent Transportation Systems (ITS) operate highly automatically. Therefore, they have to be able to handle a large variety of situations each demanding a particular system behavior. That aggravates the development of control software that has to guarantee safe and expedient operation in all possible situations. To support a suitable reconfiguration of the controllers to changing environments, the use of self-adaptation seems to be a highly promising approach. In this paper, we propose to combine model-based engineering of control software with simulation. That allows us to create and test controller software in parallel with the physical systems, it shall operate. Moreover, this approach makes it possible to safely confront a transport system with situations that, otherwise, could only be reproduced taking a significant risk. In particular, we introduce a framework for the creation of control software using simulators together with a development structure. The suggested design process is illustrated with a mobile robot example.
{"title":"Simulation-driven Development of Self-adaptive Transportation Systems","authors":"M. Oplenskedal, P. Herrmann, J. Blech, Amirhosein Taherkordi","doi":"10.1109/NETSOFT.2018.8460073","DOIUrl":"https://doi.org/10.1109/NETSOFT.2018.8460073","url":null,"abstract":"Modern Intelligent Transportation Systems (ITS) operate highly automatically. Therefore, they have to be able to handle a large variety of situations each demanding a particular system behavior. That aggravates the development of control software that has to guarantee safe and expedient operation in all possible situations. To support a suitable reconfiguration of the controllers to changing environments, the use of self-adaptation seems to be a highly promising approach. In this paper, we propose to combine model-based engineering of control software with simulation. That allows us to create and test controller software in parallel with the physical systems, it shall operate. Moreover, this approach makes it possible to safely confront a transport system with situations that, otherwise, could only be reproduced taking a significant risk. In particular, we introduce a framework for the creation of control software using simulators together with a development structure. The suggested design process is illustrated with a mobile robot example.","PeriodicalId":333377,"journal":{"name":"2018 4th IEEE Conference on Network Softwarization and Workshops (NetSoft)","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114961126","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-06-01DOI: 10.1109/NETSOFT.2018.8460007
Manuel Peuster, Hannes Kuttner, H. Karl
Dynamically steering flows through virtualized network function instances is a key enabler for elastic, on-demand deployments of virtualized network functions. This becomes particular challenging when stateful functions are involved, necessitating state management. The problem with existing solutions is that they typically embrace state migration and flow rerouting jointly, imposing a huge set of requirements on the on-boarded VNFs, e.g., solution-specific state management interfaces. In this paper, we introduce the seamless handover protocol (SHarP). It provides an easy-to-use, loss-less, and order-preserving flow rerouting mechanism that is not fixed to a single state management approach. This allows VNF vendors to implement or use the state management solution of their choice. SHarP supports these solutions with additional information when flows are migrated. Further, we show how SHarP significantly reduces the buffer usage at a central (SDN) controller, which is a typical bottleneck in existing solutions. Our experiments show that SHarP uses a constant amount of controller buffer, irrespective of the time taken to migrate the VNF state.
{"title":"Let the state follow its flows: An SDN-based flow handover protocol to support state migration","authors":"Manuel Peuster, Hannes Kuttner, H. Karl","doi":"10.1109/NETSOFT.2018.8460007","DOIUrl":"https://doi.org/10.1109/NETSOFT.2018.8460007","url":null,"abstract":"Dynamically steering flows through virtualized network function instances is a key enabler for elastic, on-demand deployments of virtualized network functions. This becomes particular challenging when stateful functions are involved, necessitating state management. The problem with existing solutions is that they typically embrace state migration and flow rerouting jointly, imposing a huge set of requirements on the on-boarded VNFs, e.g., solution-specific state management interfaces. In this paper, we introduce the seamless handover protocol (SHarP). It provides an easy-to-use, loss-less, and order-preserving flow rerouting mechanism that is not fixed to a single state management approach. This allows VNF vendors to implement or use the state management solution of their choice. SHarP supports these solutions with additional information when flows are migrated. Further, we show how SHarP significantly reduces the buffer usage at a central (SDN) controller, which is a typical bottleneck in existing solutions. Our experiments show that SHarP uses a constant amount of controller buffer, irrespective of the time taken to migrate the VNF state.","PeriodicalId":333377,"journal":{"name":"2018 4th IEEE Conference on Network Softwarization and Workshops (NetSoft)","volume":"160 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127619446","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-06-01DOI: 10.1109/NETSOFT.2018.8460057
S. Kukliński, Lechosław Tomaszewski, Tomasz Osiński, A. Ksentini, P. A. Frangoudis, E. Cau, M. Corici
Network slicing is an important technology that influences the way in which new networking solutions will be designed and operated. Currently, there are several approaches to network slicing, but so far there is no a systematic approach that includes all aspects of the technology. In this paper, we present a generic network slicing framework that includes embedded in each slice some management and operations related mechanisms in order to cope with slice management scalability and to address the multi-tenancy issue. The presented solution uses NFV MANO for slice orchestration and supports multi-domain slicing.
{"title":"A reference architecture for network slicing","authors":"S. Kukliński, Lechosław Tomaszewski, Tomasz Osiński, A. Ksentini, P. A. Frangoudis, E. Cau, M. Corici","doi":"10.1109/NETSOFT.2018.8460057","DOIUrl":"https://doi.org/10.1109/NETSOFT.2018.8460057","url":null,"abstract":"Network slicing is an important technology that influences the way in which new networking solutions will be designed and operated. Currently, there are several approaches to network slicing, but so far there is no a systematic approach that includes all aspects of the technology. In this paper, we present a generic network slicing framework that includes embedded in each slice some management and operations related mechanisms in order to cope with slice management scalability and to address the multi-tenancy issue. The presented solution uses NFV MANO for slice orchestration and supports multi-domain slicing.","PeriodicalId":333377,"journal":{"name":"2018 4th IEEE Conference on Network Softwarization and Workshops (NetSoft)","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115712727","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-06-01DOI: 10.1109/NETSOFT.2018.8460126
A. Zeineddine, W. El-Hajj
Software-defined networking (SDN) is a newly emerging approach in computer networking which abstracts network control functionalities and enables its direct programmability at the management plane. A new framework of communication between the control-plane and the data-plane is gaining a lot of attraction recently, which combines the advantages of the proactive approach, in pre-installing the flow rules in the data-plane, and the advantages of the reactive approach, in its ability to dynamically react to network events. This hybrid approach utilizes the potential of the SDN switches to recognize and host state machines. While the trending success of SDN is set to continue, this evolving network paradigm requires a new set of tools and strategies to secure the network elements against intrusions and at the same time maintain its efficiency and reliability. In this paper, we take advantage of the hybrid approach of network controllability and management to offload the processing of stateful applications from the control-plane to the data-plane and propose our framework, SDFS, which optimizes a distributed stateful application in the data-plane to transform the SDN network into one big firewall. While maintaining modularity of the framework, SDFS offers an optimized processing burden distribution of the stateful application in the data-plane among the switches in the network with inherent fault-tolerance mechanisms that eliminate the need for immediate controller intervention even in cases of network failure or attacks.
{"title":"Stateful Distributed Firewall as a Service in SDN","authors":"A. Zeineddine, W. El-Hajj","doi":"10.1109/NETSOFT.2018.8460126","DOIUrl":"https://doi.org/10.1109/NETSOFT.2018.8460126","url":null,"abstract":"Software-defined networking (SDN) is a newly emerging approach in computer networking which abstracts network control functionalities and enables its direct programmability at the management plane. A new framework of communication between the control-plane and the data-plane is gaining a lot of attraction recently, which combines the advantages of the proactive approach, in pre-installing the flow rules in the data-plane, and the advantages of the reactive approach, in its ability to dynamically react to network events. This hybrid approach utilizes the potential of the SDN switches to recognize and host state machines. While the trending success of SDN is set to continue, this evolving network paradigm requires a new set of tools and strategies to secure the network elements against intrusions and at the same time maintain its efficiency and reliability. In this paper, we take advantage of the hybrid approach of network controllability and management to offload the processing of stateful applications from the control-plane to the data-plane and propose our framework, SDFS, which optimizes a distributed stateful application in the data-plane to transform the SDN network into one big firewall. While maintaining modularity of the framework, SDFS offers an optimized processing burden distribution of the stateful application in the data-plane among the switches in the network with inherent fault-tolerance mechanisms that eliminate the need for immediate controller intervention even in cases of network failure or attacks.","PeriodicalId":333377,"journal":{"name":"2018 4th IEEE Conference on Network Softwarization and Workshops (NetSoft)","volume":"2011 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131814475","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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