Next Generation Networks (NGNs), as envisioned by ITU-T, are packet-based networks, capable of provisioning consistent and ubiquitous services to end-users, independently of the network, the access technology and the devices used. RESTful Web services are now being contemplated as a technology for service provisioning in NGNs. They are emerging as an alternative, which may be more adequate than SOAPbased Web services in some cases. SOAP-based Web services are modular applications that can be discovered and invoked over a network. RESTful Web services, on the other hand, are defined as a network architectural style for distributed hypermedia systems. This paper presents a survey on RESTful Web services for service provisioning in NGNs. It introduces the concept of RESTful Web services and reviews the state-of-the-art of RESTful-based-service provisioning in NGNs. It also provides an evaluation of the overall suitability of RESTful Web services for service provisioning in NGNs, and discusses research directions. RESTful Web services do show significant potential for service provisioning in NGNs. However, open issues such as publication/discovery and mechanisms for the development of complex session-based services need to be solved before its full potential can be realized
