The dramatic increase in computing power that we have experienced in recent years has highlighted network delays in WANs as the main culprits for the negative impact on key contractual protocols. The aim of this work is to build a new protocol that negotiates the calculation effectively of communication. We are resurrecting an important agreement previously proposed by Steer et al. We are expanding it to deal with dynamic groups and network outages such as network partitions and mergers. The resulting protocol suite is clearly safe from passive opponents and offers significant independence, i.e. a passive opponent who knows that a correct set of group keys cannot detect other group keys that are not included in the subset. In addition, the protocol is simple, error-tolerant and is well suited to a large network with a high delay. CANS 2006: Cryptology and Network Security S. 73-89 Cites as This work is supported by the National Natural Science Foundation of China under Grant No.60473030, No.60473090, No.60573129, the Key Projects Foundation of Ministry of Education of China and the Foundation of Science – Technology Agency of Sichuan Province under Grant No.05JY029-131. Most of the previously proposed protocols optimize the cryptographic overhead of the protocol. However, significant delays in GAs have a negative impact on their effectiveness.