The Investigation On High Availability Environment Of Mobile Cloud Computing Based On Cloudlet Three-level Hierarchical Architecture

The development of information technology is entering the fourth phase following the age of the expert,the personal computer and the Internet.Wireless Word Research Forum(WWRF)predicts that there will be around 7trillion devices in the world by 2020,in other words,each resident will be surrounded by 1000 wireless devices.With the signification increase in the number of mobile devices and the rapid development of the application requirements,the current mobile communication architecture will soon reach the limit,mobile computing and cloud computing arise as a new computing model and are applied to various application environments.Mobile cloud computing can be seen as the result of the evolution and integration of mobile communication and wireless communication technology.With the popularity of resource-intensive mobile devices,mobile cloud computing is playing an more important role.Mobile cloud computing can make full two advantages--the resource concentration of cloud computing and the flexibility of mobile devices.However,with the rapid development of technology,modern mobile devices need to run more and more complex mobile applications to meet the needs of users.Fortunately,the emergence of "cloudlet"solved the problem of the above.The core of cloudlet is the idea of distributary of computing services.In the mobile network,cloudlet can be regarded as a small computing center on the edge of the network,and it helps mobile devices to offload computing tasks to back-end VMs provided by cloudlet.However,in increasingly complex deployment environments and usage scenarios,cloudlet system can easily go down and become unavailable due to various natural or man-made factors.Therefore,it is necessary to conduct relevant research on the high availability of mobile cloud computing system environment.The core of solving the high availability environment problem of mobile cloud computing system is to ensure the sustainability of mobile cloud computing services.Since the core services of mobile cloud computing system is the computing split-flow function and service of cloudlet back-end virtual server,because the key point of mobile cloud computing high availability environment is to ensure the sustainability of this function and service.Traditional VM service high availability technology is mainly realized through VM migration technology(including cold migration and hot migration).The proposed "VM hand-off" technology based on above technologies also provides technical support for the sustainability of mobile cloud computing services.However,due to the rapid increase in the complexity of mobile cloud computing system environment,the VM hand-off with complex architecture,long migration time and large amount of data transmission is difficult to be applicable to the demand of high availability environment of mobile cloud computing system.This paper focuses on the research of mobile cloud computing,high-availability environment based on the cloudlet three-level model,deeply studies the principle and mechanism of the cloudlet three-level model,and optimizes the traditional VM hand-off technology from three aspects:architecture design,data transmission quantity and service migration time.A high-available system scheme for mobile cloud computing services is proposed and the analysis results are verified by experiments on OpenStack platform.The main research works are as follows:(1)The principle and architecture of cloudlet three-level model of mobile cloud computing are expounded,and three core technologies(Cloudlet Discovery,Rapid Just-In-Time VM Provisioning and VM Hand-Off)mechanism are deeply studied.This paper analyzes the factors affecting the high-availability of mobile cloud computing network,points out its optimization direction and implementation method,and puts forward the research and design scheme for the high availability of mobile cloud computing network.(2)The architecture and core project components and functions of OpenStack are introduced.This paper designs the minimum cloudlet three-level model system and mobile cloud computing high-availability system,and implement the system establishments and service verification of both,including services discovery,service configuration and service migration.(3)The high availability of two systems are analyzed,experimentally verified and compared from three aspects:system architecture design,data transmission and service migration time optimization.The results show that the high-availability system of mobile cloud computing can simplify the complexity of mobile network,greatly reduce the service migration time and the amount of data transmission in the migration process,so as to avoid data storm and network congestion,and improve the network robustness and sustainability of mobile computing services.