A method for monitoring tunneled Internet Protocol (IP) traffic in a communication network includes monitoring tunnel signaling flows to determine relationships between tunnels and subscriber sessions for each established tunnel. A first tunnel signaling state is stored in a data repository for each established tunnel. The first tunnel signaling state is indicative of the determined relationship between the tunnel and corresponding subscriber sessions. A second tunnel signaling state is validated based on the stored first tunnel signaling state to identify incorrect association between a monitored tunnel and corresponding subscriber session, in response to detecting a monitoring gap.