Towards Reliable Remote Laboratory Experiences: A Model for Maximizing Availability Through Fault-Detection and Replication

Educational remote laboratories allow users to access and control via the Internet remote equipment, that may be physically located anywhere in the world. They have a great potential for education, since they offer many advantages, such as cost reduction, high flexibility or the possibility of sharing equipment among institutions. However, their use is not yet as widespread as it could be. Freely available laboratories often present significant reliability issues. Instructors often plan their lessons in advance, and incorporating third-party tools that are prone to failure is risky, since they may be unavailable for the class and present errors to the students, which may make it necessary to suspend the session or find alternatives on the go. This contribution analyzes the reliability of a set of state-of-the-art laboratories with a view to categorizing and quantifying the most common failures. It then describes a multi-layered software model for detecting errors in laboratories. This model has two main goals. First, to ensure that the laboratory management system is aware of the state of the laboratory, so that users do not experience errors and laboratory maintenance personnel can repair it as soon as possible. Second, to serve as a base for a fault-tolerance model that leverages replicated instances of the laboratory. This fault-tolerance model is also described, and is designed to provide high availability and support for multiple concurrent users. The effectiveness of this model is validated by analyzing the reliability and availability of two remote laboratories in which it has been implemented.