Turning optical networks into sensing platforms
Networks have long been designed to transport data as efficiently and reliably as possible. A new innovation in optical networking, optical network tomography, makes it possible to use these same networks for detecting anomalies in the network. Developed by Nokia Bell Labs and validated in a large-scale field trial with CSC – IT Center for Science in Finland, Sikt – Norwegian Agency for Shared Services in Education and Research, and SUNET (Swedish University Computer Network), the technology enables operators to extract detailed insights directly from live data traffic, without requiring additional measurement equipment.
Seeing inside the network
Tomography works by analyzing signal distortions to reconstruct a detailed, span-by-span view of the optical network. It leverages advanced algorithms to “see” inside the network. This allows operators to infer fiber characteristics, amplifier locations, and signal behavior across thousands of kilometers, even in networks where topology is only partially known, or not known at all, such as in multi-domain environments. Even small anomalies can be identified and localized before they escalate.
The extensive field trial spanning more than 2,000 kilometers demonstrated that tomography can accurately map real-world infrastructure, aligning closely with physical measurements. Importantly, this can be achieved using existing coherent transponders and live traffic, making it a cost-efficient and scalable solution for future needs also for research and education networks.
An active source of operational intelligence
For CSC and similar research and education network operators, this represents an interesting possibility: optical infrastructure would no longer be just a passive transport layer, but an active source of operational intelligence. It adds a layer that can improve the infrastructure security and resilience. Tomography enables continuous physical-layer monitoring, making it possible to detect unusual signal behavior that could indicate fiber damage or even unauthorized access.
As networks grow more complex, distributed, and critical for scientific computing, data-intensive research, and cross-border collaboration, the need for deeper, real-time infrastructure insight becomes increasingly important. Innovations like optical network tomography can help in detecting early signs of degradation and potential issues. While further development is needed, the trial has confirmed that tomography can deliver accurate, real-time insight into optical networks at scale.
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