Optical performance monitoring

Abstract

This chapter explores optical performance monitoring (OPM) and its potential for enabling higher stability, reconfigurability, and flexibility in a self-managed optical network. Fundamentally, OPM is a potential mechanism to improve control of transmission and physical-layer fault management, which is essential for the operation of complex WDM transmission and switching systems. To enable robust and cost-effective automated operation, the network should probably be able to intelligently monitor the physical state of the network as well as the quality of propagating data signals, automatically diagnose and repair the network, allocate resources, and redirect traffic. To achieve this, OPM should isolate the specific cause and location of the problem rather than simply sound an alarm. To enable robust and stable operation, the monitoring information corresponding to the accumulated impairment due to each specific degrading effect should probably be deployed ubiquitously around the network. A network feature that might be desirable is for the monitor to be independent of the data format to accommodate a convergence of different traffic types, which point out that OPM should accommodate transparency. It might also be required to provide valuable information such that routing tables themselves can dynamically reflect the state of the physical links, the fidelity of the channels, and the addition/deletion of nodes. Monitoring might provide enhanced security to initiate preventive measures against denial-of-service, either through human error or malicious attack. The value of monitoring increases with increasing intelligence and bit rates. And the right balance should be maintained between monitoring coverage, sensitivity, and cost. © 2008 Elsevier Inc. All rights reserved.