Computer networks serve billions of users all over the world. Research in this field could be performed by building test beds in labs. However, this approach is very expensive, inflexible and hard to reconfigure. It is also difficult and sometimes impossible to replicate some scenarios with test beds. Network simulation on the other hand overcomes all these difficulties. Network simulation can be easily used to study and debug network protocols, understand their interaction and predict how network changes will affect performance. In this paper, we introduce the Event-Driven Network Architecture Simulator, EDNAS. EDNAS is a general-purpose, portable and scalable simulator. We discuss its architecture and implementation. We demonstrate and analyze the results EDNAS provides using various performance measures that are hard to obtain using analytical models. This makes EDNAS very appealing in the study of communication networks.