One of the most important and difficult issues involved with the optical network is network management for several reasons: restoration, performance, and wavelength services. Although network management of optical networks is a topic too large to cover extensively in an optical network tutorial, some of the important issues are briefly discussed in this module.

First, the optical network is evolving and being implemented on top of an existing SONET architecture, which provides its own restoration and protection schemes. Without a highly intelligent network-management system (NMS), it becomes extremely difficult to ensure that restoration schemes between the electrical and optical layer do not conflict. In addition to mediation between the optical and SONET layer, the network management system must be able to prevent possible conflicts or, at the minimum, enable the service provider to identify conflicts.

In addition to managing the overall network architecture, NMSs must be able to monitor signal performance for each wavelength. With the addition of optical add/drop multiplexers and optical cross-connects, the end-to-end performance of wavelengths becomes more difficult. NMSs for the optical network must assist providers in troubleshooting the network by isolating questionable wavelengths and the possible location of degradation. As the number of wavelengths on each fiber approaches 40 or more, it is important to have an intelligent method to monitor all of them.

Finally, and perhaps most important to the service providers, the ability to manage and provide new services to customers quickly is crucial. As discussed earlier, provisioning end-to-end services can be difficult, especially as network capacity decreases. An intelligent NMS can help providers establish and monitor new end-to-end wavelength services to maximize their bandwidth revenues.