Chapter 3 - Optical Path Cross-Connect

Abstract

The concept of the path is of critical importance in the context of traffic engineering techniques developed for transport networks. Path control can be performed with add/drop multiplexer (ADM) systems, digital cross-connect systems, and network operation systems. Paths also provide an effective means of implementing virtual private networks (VPNs). Path is fundamentally a logical concept the attributes of which are the bandwidth, route, and quality of service (QoS) that it provides. Optical paths are identified by their wavelengths. Optical paths can make quantum leaps in both transmission capacity and cross-connect throughput simultaneously by exploiting the wavelength-division multiplexing (WDM) transmission and the wavelength routing capabilities of paths. The optical path cross-connect (OPXC) system is key to realizing the WDM optical path network because it acts as the transport node. The typical OPXC system consists of optical cross-connect (OXC), wavelength conversion (W/C), WDM transmission (WDM-T), and payload assembler/disassembler (PAD) functions. Developing an OPXC system is likely to lead the way to a higher level of optical-path control in mesh-like topology networks. A network operation system can ensure fast restoration or reconfiguration on a per-optical path basis as well as providing an automatic protection mechanism for optical paths.