Software Engineering Institute

Next-generation networks are expected to support a wide variety of services. Some services such as video, voice, and plant control traffic have explicit timing requirements on a per-message basis rather than on the average. In this paper, we develop a general model of reservation-based dual-link networks to support real-time communication. We examine the desirable properties of this network and the difficulties in achieving these properties. We then introduce the concept of coherence and develop a theory of coherent dual-link networks. We show that a coherent dual-link network can be analyzed as though it is a centralized system. We then discuss practical considerations in implementing a dual-link network, and implications of this work to address problems observed in the IEEE 802.6 metropolitan area network standard.