November2000 N for the Price of 1: Bundling Web Objects for More Eecient Content Delivery 1

Persistent connections address ine ciencies associated with multiple concurrent connections. They can improve response time when successfully used with pipelining to retrieve a set of objects from a Web server. In practice, however, there is inconsistent support for persistent connections, particularly with pipelining, from Web servers, user agents, and intermediaries. Web browsers continue to open multiple concurrent TCP connections to the same server. This paper proposes a new idea of packaging the set of objects embedded on a Web page into a single bundle object for retrieval by clients. Our analysis indicates that if embedded objects on a Web page are delivered to clients as a single bundle, the response time experienced by the clients is as good as or better than that provided by currently deployed mechanisms. We also show that, relative to the currently used retrieval methods, our approach reduces the load on the network and servers. The key contribution of our work is a mechanism that gives Web servers control over the number and duration of TCP connections they support. Implementation of the mechanism requires no changes to the HTTP protocol.