r sourced, centralized systems to specialized, multi-vendor, distributed and integrated systems is well under way. This move from custom-built OSS solutions of the past to COTS-based solutions of present was largely driven by cost, time-to-market and flexibility reasons. The previous generation of OSSs assumed a fairly static world of mostly circuit-switched voice. The current generation of OSSs is geared towards providing flexibility whereby the system can be configured and customized to fit a carrier's need and can accommodate variations in products and services, network technologies and business processes. We constantly see that OSSs lag behind the growth in networks and services and hence have to be "patched" and "fixed" to support this evolution. In fact, deficiencies in OSS applications are often the primary bottleneck for delivery of newer services by carriers. The current, dramatic network infrastructure evolution will make many existing OSSs obsolete and force them to be replaced rather than adapted. The OSS of today will make way for a new era of systems - Next-Generation OSS (NGN OSS). The NGN OSS will be required to support the next-generation network: an intelligent IP-based core infrastructure proving QOS and policy-based services. The next-generation network will be a convergence of the telecom and Internet environments and will provide an infrastructure for not only development of newer services but also let migration of "old" and traditional circuit-switched services. These networks will place new requirements on the OSS - support for new tiered services, multiple networking technologies, QOS and policy-based management, auto-discovery and inventory, SLA management and usage-based billing to name a few. The NGN OSS will have to be developed with a different paradigm in mind - that of intelligent, converged networks. To build these OSSs for the new era, we can take advantage of advancements in computing technologies and new Web-based services standards such as XML, SOAP, UDDI and J2EE to create op