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The Optical Network Emulation (ONE) engine is a software tool that offers students the opportunity to learn how to control and operate open optical (wavelength division multiplexing) transport networks, such as those based on the Open ROADM MSA standards. This paper describes multiple modelling techniques that are implemented in the ONE engine to represent the signal power spectral density at any link/fiber section of the emulated transport network. These techniques make use of polynomial fitting and deconvolution computation methods. 

With the emergence of IoT applications, 5G, and edge computing, network resource allocation has shifted toward the edge, bringing services closer to the end users. These applications often require communication with the core network for purposes that include cloud storage, compute offloading, 5G-and-Beyond transport communication between centralized unit (CU), distributed unit (DU) and core network, centralized network monitoring and management, etc. As the number of these services increases, efficient and reliable connectivity between the edge and core networks is of the essence. Wavelength Division Multiplexing (WDM) is a well-suited technology for transferring large amounts of data by simultaneously transmitting several wavelength-multiplexed data streams over each single fiber optics link. WDM is the technology of choice in mid-haul and long-haul transmission networks, including edge-to-core networks, to offer increased transport capacity. Optical networks are prone to failures of components such as network fiber links, sites, and transmission ports. A single network element failure alone can cause significant traffic loss due to the disruption of many active data flows. Thus, fault-tolerant and reliable network designs remain a priority. The architecture called “dual-hub and dual-spoke” is often used in metro area networks (MANs). A dual-hub, or in general a multi-hub network, consists of a set of designated destination nodes (hubs) in which the data traffic from all other nodes (the peripherals) should be directed to the hubs. Multiple hubs offer redundant connectivity to and from the core or wide area network (WAN) through geographical diversity. The routing of the connections (also known as lightpaths) between the peripheral node and the hubs has to be carefully computed to maximize path diversity across the edge-to-core network. This means that whenever possible the established redundant lightpaths must not contain a common Shared Risk Link Group (SRLG). An algorithm is proposed to compute the most reliable set of SRLG disjoint shortest paths from any peripheral to all hubs. The proposed algorithm can also be used to evaluate the overall edge-to-core network reliability quantified through a newly introduced figure of merit. 

Continuous monitoring of key network elements is instrumental in intelligent control and predictive analysis. This demonstration illustrates implementation challenges that are encountered in cross-layer monitoring of optical transport networks in an open-source network operations platform. 

The Optical Network Emulation (ONE) engine is a real-time and realistic platform for testing functionalities and FCAPS features of OpenROADM controllers. Its decentralized architecture, potential applications, and educational purposes are discussed in this paper. 

The Open ROADM ecosystem enables greater flexibility in deploying optical networks through centralized SDN management and intelligent service orchestration. However, since the maintenance signaling is yet to be standardized and implemented within each device, it is difficult to identify the root cause of issues and manage the network effectively when faults propagate in the network. To tackle this problem, this paper presents a proof-of-concept implementation of an alarm correlation and ticketing system for the multi-vendor Open ROADM ecosystem. The proposed system uses a graph-based method to identify the root cause of alarms and generate tickets for network operations teams. The results of our laboratory tests demonstrate the effectiveness of the proposed system in managing alarms in the multi-vendor Open ROADM ecosystem.