A Load Reduction System to Mitigate Flash Crowds on Web Server

In recent years there is a rapid increase of traffic to a given web server within a short time as the number of Internet users increases, and such a phenomenon is called a flash crowd. Once flash crowds occur in the web server, a response rate decreases or the web server may crash as the load increases. We propose a load reduction system, which prevents excessive accesses and stably delivers content without enhancing the performance of the web server even when flash crowds occur. In the proposed system, a proxy server detects flash crowds by monitoring the number of requests and changes a content delivery system. To limit accesses to the web server, the proxy server redirects a request to another client that holds the content in the cache when flash crowds occur. We also propose a content delivery system that uses a tree construction to reduce the client load. Moreover, its efficacy is shown through simulations.