IISO/IEC 9594-8 defines the public key framework and attribute certificate framework. Attribute certificate framework deals with privilege management infrastructure(PMI). In PMI, for privilege management using attribute certificates, role assignment certificates and role specification certificates are used to assign and specify privileges independently. Role specification certificates includes privilege specifications and the details far privilege management of network environments. Privilege management of unreliable network environment tries to enhance the reliability and efficiency of privilege information transmission forwarding over unreliable routes in the presence of potentially faulty nodes and edges. Each node forms a role specification tree based on role specification relationship data collected from the network. In this paper privilege management cost with the role specification certificates tree structure is evaluated trying to reduce the overhead incurred by role creation and modification of privileges. The multicasting of packets are used for scalability. We establish management cost model taking into account the packet loss and node reliability which continuously join and leave for network. We present quantitative results which demonstrate the effectiveness of the proposed privilege management scheme.