The real-time applications with security requirements are emerging in various areas including government, education and business. However, conventional real-time scheduling algorithms failed to fulfill the security requirements of real-time applications. In this paper, a GAIA methodology that analyses and design multi-agent system. This methodology combines the functionality of real time scheduling with security service enhancement. The scheduling uses differentiated earliest deadline first scheduler. And for security service enhancement uses congestion control mechanism. Real-time systems require high Quality of Security (a dimension of QoS) to guarantee the data processing on clusters not being read or altered by malicious users.