This book deals with conformance testing for verification and validation of protocols for communication/distributed computer systems. The reader is introduced to this topic using the Finite State Machine (FSM) model together with a comprehensive review of past and current work. A detailed treatment of graph approaches for vector generation and fault coverage evaluation is presented using examples with real protocols.Qualitative and quantitative measures are introduced to quantify and compare these approaches, inclusive of the length of the generated test sequence and fault detection capabilities. Different techniques such as the Rural Chinese Postman Tour and compaction by test overlapping, are fully analyzed for achieving the desired figures of merit.Novel analytical frameworks such as the fault model and the test sequence generation, are proposed to facilitate a better understanding of the conformance testing process for the practicing engineer as well as an academic audience.