A Survey On Load Balancing Based On Mobile Agents In Distributed Web Servers

Users on the distributed web servers over the Internet demand for high scalability, availability, throughput and better response time for their requests. This is achieved by using load balancing techniques, which uniformly distributes the client requests to the web servers organized into a cluster. A cluster is a group of physical servers with identical content, networked together to form a single virtual server. A distributed web servers is a collection of replicated servers located at same or different sites and associated by the communication media. Web servers located at same site are organized into a cluster is distributed LAN web servers where as web servers are deployed in different geographical locations are structured as distributed WAN web servers. Load balancing strategies on distributed web servers are implemented in two ways namely message passing and mobile agent paradigm. In message passing paradigm, web servers have to exchange numerous messages on load periodically in order to finalize the processing of a request in any one of the server in a cluster. Alternative approach for message passing is the mobile agent based approaches. A mobile agent is a software component that can move freely from one host to another on a heterogeneous network and transport its state and code from home host to other host and execute various operations on the site. The advantages of using mobile agents over message passing paradigm are low network traffic, supports asynchronous and autonomous operations. This paper discusses about the various techniques of load balancing based on mobile agents. Key words: Load balancing, Message passing, Mobile Agents, Distributed system.