Fault tolerance has become more crucial because almost every corporate sector uses internet services to transmit critical information over the internet. The relationship between fault categories and their characteristics is convoluted as a result of the fuzziness of faults. Therefore, a difficult aspect of diagnosis using the conventional method is identifying the defect type. Over the past two decades, several ways have been developed to address the high dependability of systems, however, the bulk of these methodologies are either theoretical or unworkable. Examining the validity and plausibility of the model using AHP & TOPSIS was the review's driving force. Here, we used the Analytic Hierarchy Process (AHP) and Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) for fault-tolerance, two specific multi-criteria decision-making techniques. Here we will see the combined results of AHP and the TOPSIS for fault tolerance.