ITU‐T's Technical Reports and Specifications 283 2.5.7 Transmission Network The sole purpose of the transmission network in Smart City Network is to provide high capacity connectivity between different Datacenters and POPs where OLTs and other Access Aggregation equipments are installed. DWDM is the preferred technology with 100G, 40G and 10G Ethernet carrying Wavelengths. Additionally, DWDM can be deployed in Ring and Mesh to provide redundancy on Layer‐0. ODN Network consists of Fiber optic cables, ODFs, Cabinets, Splitters and related accessories. ODN network is designed to provide Type‐B protected connectivity to the residential subscribers towards the OLTs at Aggregation and Datacenter Sites. Splitters with 1:32 split ratio are used to provide 80Mbps connectivity to residential subscribers. OLS (Optical Line Supervisor) systems are deployed to monitor the fiber optic cable. Any fiber cuts occurring in the ODN Network are immediately identified by the OLS (e.g., N2510) system and field staff is informed to rectify the faults. If Customer shows interest in Huawei's ODN Solution then iODN Solution should be presented. Generally it has been learnt that Network operator's do the design for ODN themselves or via some 3rd party consultants. Business users are provided P‐to‐P connectivity to provide GE level connectivity on fiber. Redundant fibers are used to provide protected connectivity. 2.5.8 Network Management System Open Access Network involves interoperation across carriers and wholesale of triple‐play services. These scenarios require comprehensive network management and O&M solutions to ensure network manageability and maintainability. Smooth deployment of wholesale services and rapid fault locating has become major concerns. The Network Management system is located at the NE management layer and the network management layer in the telecommunication management network (TMN). It has all NE‐level and network‐level management functions. Figure below, shows the positioning of the NM in the TMN. Figure 48 – Positioning of the NM in the TMN