Formal Verification of Receiver Initiated Load Distribution Protocol with Fault Tolerance and Recovery using Event-B

1078-1090Load distribution is a process that involves the allocation of tasks to various nodes in the distributed system in such a manner that overall resource utilization is maximized, and overall response time is minimized. This paper presents a formal model for verification of receiver-initiated load balancing and fault tolerance protocol with recovery in distributed systems using the eclipse-based Event-B platform called Rodin. Here, the receiver-initiated load balancing approach is demonstrated along with tolerance of node failure and recovery. In this approach, an underloaded node (receiver) initiates the process of load transfer from an overloaded node (sender). The underloaded node broadcasts a request message to obtain load from the overloaded nodes. The overloaded nodes reply with their load value. The underloaded node then selects the optimal overloaded node for load transfer. The chances of node failure are minimized by reducing the number of overloaded nodes. The process of recovery from failure is also shown in the proposed model. Formal methods are used to mathematically verify the critical properties of the system by developing a model based on its specifications. Our objective is to verify and validate the model for correctness through discharge of proof obligations using Event-B. Event-B is a formal method which is used for verification of a model based on distributed systems. The proof obligations generated by the model are discharged which ensures the correctness of our model

Rigorous Design of Fault Tolerance and Recovery Algorithm for Disaster Management and Relief Distribution System using Event-B

518-529India is vulnerable to disasters such as earthquakes, floods, tsunamis, landslides forest fires and cyclones due to its unique socio-economic and geo-climatic conditions. Twenty seven out of thirty-six states and union territories are prone to different types of disasters which cause loss of life, disruption of livelihoods, damage to infrastructure and property which in turn becomes a heavy burden on the national economy. Effective management of relief work is a key step towards normalizing human life post disaster. In this paper, we have presented the formal development and verification of a fault tolerance and recovery algorithm for district level disaster control centers in India which are connected to each other via a communication network. Formal methods help in the verification of critical properties of complex systems by developing mathematical models so that design errors can be detected and removed during the early stages of software development. Event-B, which is a formal method and Rodin platform is used for this work. Event-B is a mathematical language of first-order logic to provide a solution to the complex algorithms formally. In this algorithm a Disaster Control Centre is chosen as the coordinator based on its unique vote value. This vote value is allotted and modified dynamically based on the extent of damage in the area where the center is located. The center having the highest vote value among the currently active centers is elected as the coordinator. The correctness of the algorithm is verified through discharge of proof obligations generated by the Event-B model

MODELING OF DISTRIBUTED MUTUAL EXCLUSION SYSTEM USING EVENT-B

The problem of mutual exclusion arises in distributed systems whenever shared resources are concurrently accessed by several sites. For correctness, it is required that shared resource must be accessed by a single site at a time. To decide, which site execute the critical section next, each site communicate with a set of other sites. A systematic approach is essential to formulate an accurate speciation. Formal methods are mathematical techniques that provide systematic approach for building and verification of model. We have used Event-B as a for-mal technique for construction of our model. Event-B is event driven approach which is used to develop formal models of distributed systems.It supports generation and discharge of proof obligations arising due to consistency checking. In this paper, we outline a formal construction of model of Lamport's mutual exclusion algorithm for distributed system using Event-B. We have considered vector clock instead of using Lam-port's scalar clock for the purpose of message's time stamping

Rigorous Design of Fault Tolerance and Recovery Algorithm for Disaster Management and Relief Distribution System using Event-B

India is vulnerable to disasters such as earthquakes, floods, tsunamis, landslides forest fires and cyclones due to its unique socio-economic and geo-climatic conditions. Twenty seven out of thirty-six states and union territories are prone to different types of disasters which cause loss of life, disruption of livelihoods, damage to infrastructure and property which in turn becomes a heavy burden on the national economy. Effective management of relief work is a key step towards normalizing human life post disaster. In this paper, we have presented the formal development and verification of a fault tolerance and recovery algorithm for district level disaster control centers in India which are connected to each other via a communication network. Formal methods help in the verification of critical properties of complex systems by developing mathematical models so that design errors can be detected and removed during the early stages of software development. Event-B, which is a formal method and Rodin platform is used for this work. Event-B is a mathematical language of first-order logic to provide a solution to the complex algorithms formally. In this algorithm a Disaster Control Centre is chosen as the coordinator based on its unique vote value. This vote value is allotted and modified dynamically based on the extent of damage in the area where the center is located. The center having the highest vote value among the currently active centers is elected as the coordinator. The correctness of the algorithm is verified through discharge of proof obligations generated by the Event-B model

Distributed systems, Formal methods, Load balancing, Proof obligations, Rodin, Verification

Load distribution is a process that involves the allocation of tasks to various nodes in the distributed system in such a manner that overall resource utilization is maximized, and overall response time is minimized. This paper presents a formal model for verification of receiver-initiated load balancing and fault tolerance protocol with recovery in distributed systems using the eclipse-based Event-B platform called Rodin. Here, the receiver-initiated load balancing approach is demonstrated along with tolerance of node failure and recovery. In this approach, an underloaded node (receiver) initiates the process of load transfer from an overloaded node (sender). The underloaded node broadcasts a request message to obtain load from the overloaded nodes. The overloaded nodes reply with their load value. The underloaded node then selects the optimal overloaded node for load transfer. The chances of node failure are minimized by reducing the number of overloaded nodes. The process of recovery from failure is also shown in the proposed model. Formal methods are used to mathematically verify the critical properties of the system by developing a model based on its specifications. Our objective is to verify and validate the model for correctness through discharge of proof obligations using Event-B. Event-B is a formal method which is used for verification of a model based on distributed systems. The proof obligations generated by the model are discharged which ensures the correctness of our model