In this work we present a real time SIP network simulation and monitoring system. The SIP network simulator is based on a probabilistic generative model that mimics a social network of VoIP subscribers calling each other at random times. The monitoring system, installed at a SIP server, provides services for collecting network data and server statistics in real time. The system provides a robust framework for developing SIP network applications such as security monitors. Keywords: SIP networks, Network simulation, DDoS attack detection
