Zero Configuration Networking

Zero Configuration Networking

Introduction

The evolution of the IP standards suite has concentrated on achieving a reliable and scalable networking architecture. Emphasis has always been placed on mechanisms that allow decentralized administration. Individual networks have been operated with local configuration, while Internetwide configuration has been coordinated through different agencies handling registration of domain names, network numbers, and other parameters.

Network operation requires consistent configuration of all hosts and servers and normally requires centralized, knowledgeable network administration and increasingly complex configuration management services.

It is important to note that there are other networking protocol suites with different priorities and deployment characteristics. In particular the AppleTalk Protocol Suite is simple to operate in small networks, though it requires system administration in larger deployments. Automatic configuration and ease of deployment were of primary importance to AppleTalk's designers. As a consequence, AppleTalk networks can be and are used in homes, schoolrooms, small offices, and conference rooms. In short, AppleTalk is successful in environments where IP networks have been absent, since IP networks have been too complicated and costly to administer. One advantage AppleTalk has over IP is that it functions even in networks where no services have been deployed.

As computers become cheaper and more pervasive, the obvious thing to do is network them together. Many companies are investigating adding features to their products to allow communication between consumer electronics, home appliances, personal computers, telecommunications devices, and more. Until the IP suite becomes as easy to operate as the AppleTalk Protocol Suite, the notion of a networked home or office using IP is impractical. There are many new networking protocols that offer easy deployment (for devices using that technology) in very simple network topologies. This diversity complicates the integration of communicating entities into a single network -- precisely what the IP suite is supposed to achieve.

Several computer software companies have taken the initiative to enhance the IP suite to address this challenge. The IETF has begun work on zero configuration networking for IP. The goal is to allow hosts to communicate using IP without requiring any prior configuration or the presence of network services. True to the traditional architectural principals of the IP suite, care is being taken to ensure that zero configuration networking protocols and operation do not detract from the scalability of larger configured networks with fully administered services.

This paper discusses the services and configuration essential for IP networking and surveys the IP suite standards for providing configuration to IP-enabled devices. The central topic of this paper is the emergence of protocols for operation without services or configuration. Work in the area of zero configuration protocols has been motivated by new demands in the marketplace. Some architectural principles are generally agreed upon and under gird the development of standards in this area. Finally, the paper summarizes the status of this work and concludes by discussing implications for the future.