An architecture for IN-internet hybrid services

Abstract

The scenario for telecom services is undergoing a rapid change. A new set of communication services is emerging: due to the explosion of the Internet and to the dramatic increase of mobile phone markets, more and more customers are requiring new Internet-based communication services. The ability to merge the ubiquitous telephone service (terminal and personal mobility) and the friendliness (easy-to-use, easy-to-customize) of the Internet is recognized as a major driver to promote new classes of services. Users want to access multiple services over heterogeneous networks and from heterogeneous terminals. The higher flexibility in service offers as well as the possibility of a rapid introduction of new services (typical of Internet & IT worlds) are key factors that give a high competitive advantage to service providers (SPs). This article describes a supporting distributed architecture in terms of functionality and components, which enables the integration of the IN architecture and the Internet. It also describes by means of a service example – the virtual presence (VP) – the main interactions among the components that form the architecture. The developed solutions prove that the use of distributed platforms, open APIs, and object-oriented techniques are enabling factors in achieving full interoperability between heterogeneous networks and terminals.

Introduction

This work is based on ongoing experiments in EURESCOM project P909-GI “Enabling technologies for IN evolution and IN Internet integration” whose objective is to investigate the service synergy between intelligent network (IN) and Internet [1] and to implement some prototypes to test the identified solutions. This synergy has to exploit the advantages of the two approaches: on one side rapid introduction of new services, user-friendliness, higher flexibility and customization of the Internet; on the other side reliability, performance and QoS of switched telecom networks.

Telecom–IN and Internet integration can be conceived at three different levels: transport, control and management, and data. Integration at transport/media level (IP for transport) allows adaptation of CODEC (G.711, G.722, etc.) and transport of media streams over heterogeneous networks (time division multiplexing (TDM) versus real-time protocol (RTP)/UDP/IP packet streams).¹ Integration at control and management level (IP for control) enables to control, initiate and manage services across the two worlds, i.e., a click to dial service or a Web initiated call conference are examples for this kind of integration. Integration at data level (IP for data repository and retrieval) enables SPs to look at users in a single fashion regardless whether users are requesting a service, receiving invitations or messages from either of the two worlds. Examples are unified user profile (IN, mobile and Internet), unified accounting and service data. Service examples relevant for this of integration are unified messaging, unified billing between IN and Internet and virtual presence (VP).

This article describes generic functionalities to enable the provisioning of integrated IN-Internet services, and a software architecture that implements such functionalities. The proposed architecture aims at integrating available off-the-shelf products, as well as currently defined and accessible protocols and standards, by using a set of components and gateways that run on top of a common object request broker (CORBA) distributed platform.

Part of the architecture has been implemented and VP (described in Section 4) has been chosen as the service prototype to challenge it. VP can be seen as an extension and integration of IN personal number and instant messaging-like services typical of the Internet. It naturally stresses the interoperability between different kind of networks, service customization and independence from the underlying networks. For all these reasons it represents the ideal service prototype.

In the following we give a short overview on IN and the most relevant emerging standards/protocols that have been used as a basis for our architecture:

• IN [11] is an architectural concept that provides for the real-time execution of network services and customer applications in a distributed environment consisting of interconnected computers and switching systems. The rationale for it is the provisioning of a multitude of supplementary services (such as freephone, conference calling, call forwarding, and many others), which require the development of specialized applications (called service logic) along with basic call processing. Developing and deploying switch-based service logic for each supplementary service and on each single network node would be an extremely expensive (if at all possible) and time-consuming task. The clear separation of basic switching functions from service logic is reflected by the separation of service switching point (SSP) and service control point (SCP). Dialogue between SSP and SCP is ensured by a standard protocol, IN application protocol (INAP).

• H.323: The ITU H.323 [5] standard provides a foundation for audio, video, and data communication across IP-based networks. The standard addresses call control (CC), multimedia management and bandwidth management for point-to-point and multipoint conferences.

• Session initiation protocol (SIP) [4] is a lightweight, transport independent, text-based protocol that is used for multimedia CC and enhanced telephony services. SIP can establish, modify and terminate multimedia sessions or calls. SIP addresses call setup and tear down mechanisms. It is independent of the transmission of media streams between caller and callee.

• Media gateway control protocol (MeGaCo)/H.248 [3] defines the protocols that enable multimedia gateway control [14]. Multimedia gateways [14] can encompass gateways, multipoint control units or integrated voice response units.

• CORBA [7] is an object-oriented architecture, which allows applications to communicate with one another no matter where they are located. The object request broker (ORB) is the middleware that establishes the client–server relationships between objects. The ORB provides interoperability between applications in heterogeneous distributed environments and seamlessly interconnects multiple object systems.

• Telecommunication information networking architecture (TINA) [9] is an architectural standard for global telecommunication and information services. TINA is based on the integration between the telecommunication approach and the information technology approach. TINA adopts key principles of information technology, such as object-oriented paradigm, distributed processing techniques and software layering. On the other hand, TINA applies principles from the telecommunication world, such as separation between call and connection, integration between control and management, and call modeling.

• Parlay [8] is an initiative whose objective is to specify an open, technology-independent, and extensible API. It opens up the networks' signaling for public usage by encapsulating network capabilities using object technology (COM or CORBA) in order to make them visible in a secure, manageable, and billable manner to third party SPs.

• Java APIs for integrated networks (JAIN^™) [6] is a Java-based telecom framework designed for new telecom-Internet integrated services, which enables service portability across heterogeneous platforms.

It is worth remarking that a lot of initiatives are addressing IN–Internet integration related topics in a variety of standards bodies and fora. Since our approach has been as pragmatic as possible we have tried to integrate as much as possible from what is already available in terms of specifications and approaches. This work has focused in particular on API based approaches such as TINA, Parlay, and JAIN.

In summary the paper is structured as follows. Section 2 describes the architectural framework and the main functionalities it supports. Section 3 describes the software architecture components that provide those functionalities. Section 4 describes a service example, the VP, and the interactions among software components for a given use case. Section 5 draws some conclusions.