17
RESILIENT BURST RING: A NOVEL TECHNOLOGY FOR NEXT-GENERATION METROPOLITAN AREA NETWORKS
17.1 INTRODUCTION
In existence for over a decade now, the metropolitan area network (MAN) has traditionally been designed for voice transmission based on the time division multiplexing (TDM) technology. At that time, voice traffic was significantly more important than data traffic. As a result, synchronous optical network/synchronous digital hierarchy (SONET/SDH) became the dominant standard on these networks. Those technologies have been able to meet the initial requirements of MANs quite adequately, and today most of them are based on SONET/SDH technology.
With the explosion in the demand for bandwidth for data transmission, it became quite clear that SONET/SDH networks needed to be reengineered to handle data traffic in a more efficient way. The new MAN technology should connect all the various access networks and provide everything from real-time services to traditional data-transfer services. It should also provide Quality of Service (QoS) and handle any kind of traffic, from constant bit-rate traffic to packet- or cell-based traffic. While such a multiservice network would minimize overall operating costs, the existing SONET/SDH infrastructure is unfortunately unable to meet these requirements. The worst-case scenario is that the operators must maintain their legacy networks for legacy services while the new services need overlapping network infrastructure. ...
