ivity that can be done as part of this stage is to aggregate common services like a report engine for different types of data representation (see Figure 34.10). Fundamentals of EMS, NMS and OSS/BSS Topology Fault Performance User admin Billing NE configuration Fault Performance Billing handler correlation event handle management manager Configuration Fault Performance Access Billing backup reporting data report report management State/Service Subscriber discovery Event handling Threshold set Single-sign-on setting Figure 34.8 Framework having interdependent processes. Topology Fault Performance User admin Billing Fault Performance Billing configuration correlation event handle management handler manager Configuration Fault Performance Access Billing backup reporting data report management report State/service Event Threshold Single- Subscriber discovery handling sign-on setting Figure 34.9 Functions split into services in Stage 3. Fault correlation Access management RMI/IIOP Report engine Event handling Threshold Backup handler Figure 34.10 Service assembly in Stage 4. Report: NGNM Framework and Adoption Strategy GUI/NBI components Fault plug-in correlation Access management Report Backup engine handler Event Threshold (NEs) handling Service bus Service registry Figure 34.11 Enhancements on the final stage. Enhancements Now add additional components like a service registry and make the functional framework based on the SOA architecture (see Figure 34.11). This way, we can migrate from legacy NMS to unified NMS framework. The advantage of phased approach is that each stage can be tested, further split for more control. This makes the transformation less risky, more manageable, and more cost effective. Stage Description Business Benefits Stage 1: Grouping of functionality Reduced effort and cost to This stage involves splitting the legacy testing NMS solution into framework and data plug-in. The data plug-in only handles data collection from the network element based on the specific protocol. Stage 2: Make interact