ABSTRACT
Client-perceived response time is an important user experience metric for a website. The response time can be broken down into three delay contributors: network delay, processing delay, and data access delay. Network delay is the time taken for a Hypertext Transfer Protocol (HTTP) request to travel across the Internet and for the response to be returned across the Internet. Processing delay occurs at the web server side. The data access delay is the time taken for a web application to retrieve data from storage. This chapter examines caching as an alternative solution to reduce the user-perceived delay. The goal of the web cache replacement algorithm is to maximize the cache hit rate, thus the decision of what to discard must be made wisely rather than randomly. The Internet Cache Protocol (ICP) provides a mechanism for establishing complex proxy cache hierarchies. A cache digest approach was developed to solve the drawbacks of the ICP approach.
