NGSON: features, state of the art, and realization
IEEE Communications Magazine
INTRODUCTION The proliferation of the Internet has removed geographical and temporal barriers for users to access value-added applications on a global scale, and service providers have faced complicated development and costly deployment of software to support the diverse requirements and environments of users. Service-oriented architecture (SOA)  was introduced to address this problem by defining how to integrate the services (or functions) distributed over the Internet for the production of
... applications. Based on the SOA principle, the service delivery platform (SDP)  was introduced, which takes on creation, execution, delivery, and control of services. Within this technology, a composite service can be orchestrated and composed of one or more component services that are distributed in different network domains. This capability allows service providers to have rapid and flexible development of their composite services by utilizing existing component services. While SDP has been of great interest to network operators due to new revenue opportunities through offering their service enablers, such as billing and messaging for thirrd-party service providers, the traditional network infrastructures lack support in the delivery of such services because they manage the service delivery and its quality of service (QoS) support, but only in their own domains (called a silo approach). To tackle this problem, the service overlay network (SON)  was introduced, which is employed as an intermediate layer to support creation and deployment of value-added Internet services over heterogeneous networks. In the SON approach, an overlay network is built as a common infrastructure for delivery of multiple value-added services. The overlay network is constituted by strategically deployed nodes (called SON nodes), which are dedicated to provide service-specific data forwarding and control functionalities. The SON nodes are interconnected with the logical connections provided by different underlying networks. Within this infrastructure, a composite service can be created by providing its business logic (i.e., composite service specification), which defines the interactions among component services. On a request for the composite service, SON invokes each component service in the order defined in the given composite service specification and delivers the service data for the subsequent interactions with a certain QoS guarantees regardless of the operating network domain of the component service. However, the SON approach has faced an intrinsic limitation to handling of the diverse and dynamic environments of users, services, and networks which are inherent characteristics of the recent trends in computing technology. To address these limitations, next-generation SON (NGSON)  was proposed by the IEEE P1903 Working Group (WG). As an instantiation of SON, NGSON provides a framework for control and delivery of composite or component services over diverse IP-based networks (e.g., legacy IP network, P2P, and IP multimedia subsystem, IMS) with QoS support by the underlying networks. The main contribution of NGSON is to accomplish context-aware and dynamically adaptive features in the service control and ABSTRACT There have been several efforts to provide service-aware technologies in the networks, such as the service-oriented architecture and service delivery platform. These technologies were integrated with service overlay network (SON) infrastructure to support control and delivery of services over multiple network domains. However, SON has limitations in handling the increasing needs of a ubiquitous and dynamic environment of users and services. To provide better quality of experience to users in this ubiquitous and dynamic environment, next-generation SON (NGSON) was introduced to support context-aware, dynamically adaptive, and selforganizing capabilities in SON. In this article, we present an overall description of the concept of NGSON, and provide a comprehensive review of the recent standardization activities related to NGSON. By visiting our experiences in designing and developing a prototype for NGSON, the challenges and opportunities of NGSON are described.