ABSTRACT
Intrusion tolerance technology is aim to guarantee the service despite of errors occurred by attackers or arbitrary faults. Group communication in ITS(Intrusion Tolerant System) should satisfy the reliability and total-ordered properties to maintain consistency among members. But it requires additional communication overhead. To apply ITS in the real, such an overhead should be minimized not to affect the target service much. To solve the problem, we suggest newly-defined ITS group communication scheme that requires little communication overhead with satisfying properties for ITS. Our proposed “cost efficient group communication & management” mechanism is based on NACK control message to notice which message isn’t received. The proposed NACK-based mechanism shows that it requires little communication overhead especially when the system environment is stable. To evaluate the suggested mechanisms, modeling and simulation is performed, and the enhancement is achieved
