ONE-IP: techniques for hosting a service on a cluster of machines

With the explosive growth of the World Wide Web, some popular web sites are getting thousands of hits per second. As a result, clients (browsers) experience slow response times and sometimes may not be able to access some web sites at all. Upgrading the server nodes to more powerful machines may not always be cost-effective. A natural solution is to deploy a set of machines, or a cluster, and have them work together to host a single service. Such a server cluster should preferably publicize only one server name for the entire cluster so that any configuration change inside the cluster does not affect client applications. In this paper, we first discuss existing approaches to distributing client's requests for a single service to different machines in a cluster. We then propose two new techniques, collectively called ONE-IF, based on dispatching packets at the IP level. They have the advantages of fast dispatching, and ease of implementation. Ideas presented here are generic and should be applicable to other services as well. (C) 1997 Published by Elsevier Science B.V.