Research And Implementation Of Disaster Tolerance System In Digital Trunked Mobile Communications

With the rapid popularization of digital trunked mobile communication system in the field of public security, its reliability and availability is becoming more and more important. However, the existing digital trunked mobile communication system has not disaster tolerance function, neither do domestic or international companies and research institutes specialized in this field have disaster tolerance plans for digital trunked mobile communications. In order to meet the demand of reliability and availability digital trunked mobile communication system, this paper focuses on the research and implementation of the disaster tolerance system in digital trucked mobile communication.First, this paper studies the network topology and equipment module of the PDT protocol (a general standard of the digital trunked mobile communication), and infers the specification of the disaster tolerance system. Then we propose a novel disaster tolerance scheme and implement in real-world digital trunked mobile communications. The main contribution is as below:In order to solve data consistency problem in the process of data backup, a backup log and a backup state table are introduced to realize the registration of updated sequence number and the location of migrated states, which eventually effectively solve the problem of data consistency.Because the backup data volume is too big, a data compression algorithm based on the rsync algorithm, namely, bsync algorithm, is designed, which can greatly improve the efficiency of the backup.To solve disaster monitoring and system application migration, double network card and double route of heart beat mechanism and technology of the virtual IP are adopted, which can efficient meet the design requirements. As to the system restoration function, disaster tolerance modules are respectively embedded in the bootloader, OS kernel and application layer of system. A system state register is added in the hardware to realize the communications among the three layers. Finally, through cooperative work of the modules in the three layers, fault detection and system recovery are achieved during system startup and daily operations.The experimental result shows that, the implemented DTDT system can meet the performance index of the disaster tolerance and the original design requirements. But some parts of the design have large space to improve, which still needs further study.