f equipment with more vendor prod- ucts. Service providers are able to develop agile solution and improve interoperability Fundamentals of EMS, NMS and OSS/BSS using OSS/J component architecture. To software vendors it provides a common API support for across-the-board integration. This accelerates the delivery of new products, lowering integration and maintenance costs. The use of OSS/J will reduce integration costs for system integrators. Various commercial off the shelf (COTS) and legacy applications, both net- work and customer facing, are integrated by the OSS systems. OSS/J initiative works on specific application areas in OSS domain and uses J2EE, EJB, and XML technologies for its development. APIs and message structures are defined for each application by the implantation group SO that the OSS components can be devel- oped and assembled into complete solutions. APIs are specified and implemented as EJB components. OSS applications are developed using these APIs. OSS/J is emerging as a widely accepted OSS/BSS standard that helps Telco to realize standardization of interface, benefiting the service providers with vendor independence. OSS systems developed the integration approach and construction approach using J2EE technology. Integration approach is intended to integrate existing applications. Construction approach develops EJB-based applications, where both application and its serving components are in the container. Easier portability and rapid application development are possible through EJB. Based on the standardized APIs, it is possible to develop vendor independent EJB connectors for various protocols like CMIP, SNMP, TL1, and the knowledge can be reused for multiple OSS/J systems. Developing EJB connectors itself as COTs components offers many opportunities and the knowledge can be reused for devel- oping connectors for proprietary protocols also. OSS/J model can address the impact of the emergence of rapid service creation environments like IP multimedia subsystems (IMS) and service delivery platf