NTT Research and Development 2008 Review of Activities

Have you ever had the experience of trying to access a Web page that never appears or of having lost a connection during a process? A sudden surge in accesses can hang up a Web server, reducing its performance and making it unable to respond satisfactorily. In particular, Web servers that provide multiple services may become unable to provide their own services due to the effects of concentrated access to other services.

Web access shaping technology measures the actual traffic of servers and balances load by restricting requests to servers that have poor response while sending requests to servers with good response (light load), thus achieving ideal load control and distribution across the overall Web system, including the back-end servers. Even when multiple services are provided, controlling the flow of requests to each service allows fair use of the server capacity by the different services, thus averting the ill effects of mixed services. Furthermore, cookie^*1 and URI^*2 information is used to give priority to requests of the member customers and the customers who were engaged in a process in order not to interrupt their connections. In the case of even greater congestion, the system returns a busy message to the customer or a numbered ticket is issued to indicate the place in the queue for reconnection. This processing prevents excessive server load due to access congestion. It also eliminates customer exasperation through notification of a Web site's busy condition.

The basic function of Web access shaping has been released to NTT Advanced Technology Corporation and is already being implemented. The ticketing of the reconnect queue and multiple service fairness functions has already been completed and implementation is planned within 2008.

• *1 cookie: An identifier assigned by a Web site to distinguish individual customers that access the site. The cookie is stored temporarily by the Web browser on the customer's computer and is appended to requests sent from the browser to the Web site.
• *2 URI: Uniform Resource Identifier (An identifier that indicates an access protocol and information such as the server name, the name of the directory in the server and the file name when they exist.) (Example) http://www.example.com/example/index.html