Research On Reliable Algorithm Of Mobile Agent System

With the development of computer network, traditional distributed computingmodel can not meet customers’ requirements and a new intelligent distributedcomputing model is wanted. In that situation, Mobile-Agent-based computing modelis presented. The Mobile-Agent-based computing model has made great achievementsin fields of network management and interoperability, which overcomes the lownetwork bandwidth and high latency limitations of network, and also made up thedeficiency of the original computing model.Mobile Agent is kind of a computer program. It can migrate freely amongdifferent computers on its own and run independently. Meanwhile, it will intelligentlysearch for applicable computing, information and software resources and takeadvantage of these resources to complete certain specific tasks, by cooperating withthe delegations which represents users in the same host or subnet. Due to the limitedcapacity of one single Mobile Agent, the Mobile Agent needs to communicate witheach other and cooperate together to complete tasks. Hence, communication becomesa critical problem in Mobile Agent system. As a basic service of Mobile Agenttechnology, the reliability and efficiency of communication will directly affect theperformance of the whole Mobile Agent system. So how to assure the reliability andefficiency of communication has become a hot research of Mobile Agent technologyareaThis paper firstly introduces the primary algorithms of the Mobile Agent system,and then analyzes their disadvantages. Aiming to solve the existing problems, thispaper has proposed two improved communication algorithms:The first improvement is to present an extended algorithm based on thecentralized-forwarding mechanism. At present, there are two typical Mobile Agentcommunication algorithms based on centralized-forwarding mechanism: One iscentralized synchronization control communication algorithm. This algorithm definesthe Mobile Agent into two status: resting and moving and it only allows the HomeAgent to send messages to the resting Agents, This mechanism will result in thepostponement of messages and reduce the message process instantaneity; The other isthe centralized synchronization control communication with mobile request. Thisalgorithm only allows Mobile Agent to migrate after acquiring the permission of Home Agent, and this will severely limit the autonomous migration of Mobile Agent.Considering the above problems, this paper reports an improved algorithm to requireHome Agent to control the messages by numbering each message and transferring intothe objective Agent immediately. When the objective Agent receives a message, it willreturn a confirmed ACK containing a task number. If the Mobile Agent wants tomigrate, it could just send a new-location-labeled message to the Home Agent andthen move to the next location. This will inform the Home Agent to resend the failuremessages to other new nodes. The experimental results show that the reportedimproved algorithm not only reduces the restrictions on moving flexibility of MobileAgent, but also better the real-time delivery and execution of messages and guaranteethe reliability of communication.The second improvement is based on the existing active communicationalgorithm of Mobile Agent. The original algorithm uses prevention method to handlethe communication failure, but this will raise the communication cost and reducecommunication efficiency. The improved algorithm adopts the detection mechanismto manage the communication failure. The algorithm analysis proves that thepresented algorithm could reduce the communication cost and enhance thecommunication efficiency effectively.