Test Synthesis Applied to Performance Evaluation of Multipoint Protocols

The advent of multipoint multicast based applica tions and the growth and complexity of the Internet has complicated network protocol design and testing In this paper we present a method for automatic synthesis of worst and best case scenarios for mul tipoint protocol performance evaluation As a case study we analyze variants of the timer suppression mechanism used in multipoint protocols in the Inter net We use our method to evaluate the mechanism with respect to two performance criteria number of responses per request and response time The results are applied to examples in reliable multicast protocols The method uses a fault oriented test generation FOTG algorithm for searching the protocol and sys tem state space to synthesize the scenarios The algo rithm is based on a global nite state machine GFSM model We have extended the algorithm with tim ing semantics to handle end to end delays and address performance criteria We introduce the notion of a virtual LAN to represent the underlying multicast dis tribution tree We hope this method can serve as a model for apply ing more systematic test generation to other network protocols as well