Automatic Mapping Between Real Hardware Composition and ROADM Model for Agile Node Updates

Swift and dynamic reconfigurability of network topology, even at the optical layer, is essential for satisfying the various requirements of future networks in diverse areas (e.g., data centers, 5G/Beyond-5G/Local-5G/6G, factory-related networks, and telecom networks) and for addressing issues arising during a disaster. Because of recent efforts to disaggregate optical transport networks, various compact disaggregate blades (e.g., wavelength selective switches and optical amplifier blades) have become commercially available. In principle, such disaggregation technology enables network operators to optimize their networks precisely at the blade level according to their distinctive needs, although the management complexity can increase with the number and diversity of the managed equipment. This paper presents transformation algorithms for mapping between a reconfigurable optical add/drop multiplexer (ROADM)-based model and a disaggregate-blade-based model to realize a flexible and agile optical physical layer based on disaggregation technology without increasing control plane complexity. In this study, a disaggregate-blade-based model named functional block-based disaggregation (FBD) is used, in which the switching functionalities of individual optical components are defined by the integer linear programming (ILP) method using machine-readable GNU MathProg modeling language. By computing the ILP formula, the switching functionalities of whole nodes/networks can be analyzed; that is, the FBD model can form the ROADM-level nodal model by aggregating the individual blade models. With the developed transformation algorithms, automated network operations, including optical path establishment/removal and node structure updates, are experimentally demonstrated on a field testbed. After physically plugging in the new components, the node structure update including the logical topology information is automatically recognized within 5 min. Multi-domain cooperative optical path recovery triggered by the update is also performed.