Advanced Communications Technology and Services (ACTS), is one of the specific programmes of the "Fourth Framework Programme of European Community activities in the field of research and technological development and demonstration (1994 to 1998)". It is the focus of this EU research effort to accelerate deployment of advanced communications infrastructures and services. ACTS communications research is complemented by extensive European research in the related fields of information technology and telematics. ACTS builds on the work of the earlier RACE programmes (Research into Advanced Communications for Europe, 1985-1995), which were established to contribute to the "Introduction of lntegrated Broadband Communications in Europe. .. by 1995. " RACE broadly achieved this objective, and the required technologies started to be deployed in European countries either in specialised scientific networks or, in a few cases, as limited public services. ACTS represents a further step towards the longer term goal of realising a global Information Society. Within Europe, all the major telecommunications network operators, the leading broadcasters, cable TV operators and all the key European equipment manufacturers participate in the ACTS programme. Their enthusiasm, and sense of partnership with the major consumers of communications is leading to a shared vision of the future.

The paper aims at providing a comprehensive picture of the new set of ATM-layer services defined in parallel by the ITU-T and The ATM Forum, outlining the potential benefits that can derive, both to users and network service providers, from the availability of these new functionalities in an ATM-based network. Terminological differences between the ITU-T and ATM Forum documents are compared and clarified and the approaches to the use of quality of service parameters and classes are discussed. The so-called Service Categories (using the ATM Forum nomenclature) are Constant Bit Rate, Variable Bit Rate (VBR), Available Bit Rate (ABR) and Unspecified Bit Rate. The ABR is the newest and the one raising major discussions, as specific congestion control mechanisms, which do represent a real innovation in the ATM framework, have been defined for its support. The paper therefore introduces the ABR service in some details and discusses some still open issues and utilization perspective.

There is presently a strong expectation for the opportunities offered by the deployment of new and sophisticated telecommunication services with increasing interactivity, ranging from distributive to highly interactive, covering heterogeneous areas, like entertainment, tourism, commercial and information. The Project AMUSE (Advanced MUltimedia SErvices to residential users), which s being carried out in the framework of the Advanced Communication Technologies and Services Programme sponsored by the European Union, is proposing effective solutions to various open issues related to the implementation and provisioning of new multimedia services. After an overview of the project and the relevant platform, the paper will introduce a description of the advanced services the project is going to provide to real residential users by means of a state-of-then-art Asynchronous Transfer Mode end-to-end infrastructure. Emphasis will be put on the outcomes of the experiences gained during the first project year, stemming from the implementation and deployment of complex multimedia services developed by means of innovative authoring tools. Particular attention will be paid to the facts and findings resulting from the activities so far performed in the Italian trial island. In particular, the role of contents provisioning and service design, as well as the monitoring of service acceptance and usability by the final users are emerging as outstanding topics, even beyond network technological issues. Finally, an outline of major unsolved problems in the area of interactive multimedia s presented.

Passive Optical Networks offer quite promising results in terms of cost, robustness, flexibility and traffic concentration. The addition of Optical Amplifiers, overcame the optical budget limitations of fully passive first generation technology, enabling the extension of the PONs to up to 15000 subscribers and a 100 km distance, creating the concept of SuperPONs currently at the development stage. The larger round trip delay, as well as the high number of subscribers, coupled with the strict traffic control dictates of ATM, create very complex traffic control and management problems but at the same time open the prospects of high multiplexing gain by aggregating many relatively small connections on a shared feeder. Novel solutions are required since the tree topology and the shared feeder create new problems not encountered in non-distributed multiplexers/concentrators. Methods to resolve the VPI/VCI conflicts on the shared medium, support OAM, ensure privacy and security, police the entry to the system, and the traffic engineering issues, are the focal points of this paper.

A versatile access solution, called the Aline (Access Line), is presented. The system is based on a new concept that allows provision of Bandwidth-on-Demand as well as traditional Constant-Bit-Rate services and is mainly intended for the business area. The Aline aims to promote the penetration of broadband services and the deployment of fiber in the Access area. Scaleability and upgradeability have been carefully addressed to ensure a future-proof solution. At the same time, by supporting different types of traffic and different physical media, this is a flexible solution that meets today's mix of traffic needs.

In the multi-vendor systems, a customer connected to an Access network (AN) must be capable of selecting a specific Service Node (SN) according to the services the SN provides. The multiplicity of technologically varying AN calls for the definition of a standard reference point between the AN and the SN widely known as the V_B interface. Two versions are currently offered. The V_B5.1 is simpler to implement but is not as flexible as the V_B5.2, which supports switched connections. The V_B5.2 functionality is closely coupled to the Broadband Bearer Channel Connection Protocol (B-BCCP). The B-BCCP is used for conveying the necessary information for dynamic resource allocation, traffic policing and routing in the AN as well as for information exchange concerning the status of the AN before a new call is established by the SN. By relying on such a protocol for the exchange of information instead of intercepting and interpreting signalling messages in the AN, the architecture of the AN is simplified because the functionality related to processing is not duplicated. In this paper a prominent B- BCCP candidate is defined, called the Service node Access network Interaction Protocol.

We have made investigated a new regional Personal-Computer (PC) communication network system for residential users beyond Small Office and Home Office (SOHO)'s users. It provides a cost-effective and user-friendly PC communication environment to community members by supporting connections group communication services with customized audio-visual user-interface and contents, moreover authenticating them on the Media Access Control (MAC) destination address of the PC's. The user-interface is designed to start the PC communication without complex setup procedure. The members can use any protocol, because MAC address authentication is independent of the network layer protocol. This group communication services are offered by distributive bulletin board servers with Common Gateway Interface (CGI) and Hyper TExt Transfer Protocol (HTTP), which are distinguished from the Net News and primary bulletin board for conventional system. This paper discusses, based on a pilot experiment in a small residential area, the network congestion caused by broadcast traffic and address conflict caused by belong to plural groups at the same time and presents a solution. We also discuss the impact of a new bulletin board server derived from traffic data based on our pilot experiment for interaction and audio-visual group communication. The server is operated by specified CGI program on HTTP server and capable to support a interactive communication environment in World Wide Web.

We present a new method for obtaining stability criteria for individual queues of Token Ring LANs. Stability criteria for individual stations are necessary when, as is the case with real LANs, the traffic pattern and/or the service strategy is asymmetric. The method makes no assumption as to the nature of the traffic arrival process or the service strategy. This is particularly useful for the development of new token passing protocols, for which an upper limit to the number of packets a station is allowed to transmit has to be defined. Also, the poisson arrival assumption is relaxed, allowing other arrival processes to be investigated. For instance, we obtain the stability conditions for LANs comprising stations with batch arrival and probabilistic service strategy. Also, a LAN simulator generally requires as input the traffic loads at each station. The stability criteria can be used to validate the set of values corresponding to the loads at the stations, thus reducing the waste resulting from simulations run under unstable loads. This s particularly useful when the behavior of LANs are being studied under heavy loads. We illustrate the usefulness of our approach with a set of results from various arrival process/service strategy combinations.

Interactive multimedia systems with guaranteed service quality require complex integration of servers, broadband networks and terminals. In the future such systems might become common, even reaching individual homes but this requires development of new standards in order to achieve interpretability comparable to Internet. The task for devising standardized end-to-end solutions for interactive networked multimedia systems has been recently undertaken by the Digital Audio Visual Council (DAVIC), a body including all major players in this area. We describe the system developed by DAVIC and problems underlying its practical implementation.

The worldwide internet system seems to be the success key for the provision of real time multimedia services to both residential and business users and someone says that in such a way broadband networks will have a reason to exist. This new class of applications that use multiple media (voice, video and data) impose constraints to the global network nowadays consisting of subnets with various data links. The attention will be focused on the interconnection of IP non ATM and ATM networks. IETF and ATM forum are currently involved in the developing specifications suited to adapt the connectionless IP protocol to the connection oriented ATM protocol. First of all the link between the ATM and the IP service model has to be set in order to match the QoS and traffic requirements defined in the relative environment. A further significant topic is represented by the mapping of IP resource reservation model onto the ATM signalling and in the end it is necessary to define how the routing works when there are QoS parameters associated. This paper, considering only unicast applications, will examine the above issues taking as a starting point the situation where an host launches as call set up request with the relevant QoS and traffic descriptor and at some point a router at the edge of the ATM network has to decide how forwarding and request in order to establish an end to end link with the right capabilities. The aim is to compare the proposals emerging from different standard bodies to point out convergency or incompatibility.

The combination of interactive services and multimedia yields a wide variety of possible new services, while Asynchronous Transfer Mode (ATM) is viewed as the emerging technology capable of delivering these services to residential users. On the other hand, the provision of Internet access to home users through an ATM access network is an attractive service, due to the wide adoption of the Internet. Considering the DAVIC reference configuration and the LAN emulation standard, an end-to-end ATM urban architecture providing interactive multimedia services is shown to be able to provide Internet access to residential users as well. In this paper, different ways to provide access to Internet are presented.

In the framework of the European ACTS (Advanced Communication Technologies and Services) program, the large project AMUSE has been established involving 25 partners from 8 European countries and Israel. The project aims to develop, specify, implement and trial advanced multimedia services to test these new services under real conditions in field trials in several locations based on Hybrid Fiber Coax (HFC), Asymmetrical Digital Subscriber Line and Fiber to the Curb/Building technologies and finally to show the implementation of an end-to-end ATM infrastructure for various types of access networks. This paper describes the first of a series of the project's HFC trials which has been carried out in the city of Munich, Germany.

This paper reports on the current technological status and future trend of those optical devices that are crucial for the development of the future optical communication technology. Particular emphasis has been dedicated to identify the active and passive optical components that are needed in advanced optical networks. The discussion of their physical and practical limitations is also subject of this article, as it is felt that these issues will ultimately have a considerable impact on the progress of the future fiber based telecommunication infrastructure.

Pulse propagation in the presence of spectral filtering, two-photon absorption, linear and nonlinear gain is investigated both for anomalous and normal dispersion regime. We analyze the steady-state pulse propagation in such a system and we observe that both the soliton chirp and width are significantly larger for normal than for anomalous dispersion. An unexpected singularity of the soliton amplitude and its width is observed in the anomalous dispersion regime when the net linear gain vanishes. We also show that arbitrary-amplitude solitons can propagate in this dispersion regime for a given relation between spectral filtering, nonlinear gain and two-photon absorption.

Bi-directional, full duplex transceiver InP/GaInAsP-PIC architectures with high crosstalk suppression ratio values for single and dual spectral window operation (1.3 micrometers and 1.5 micrometers ) are reported as well as simulation calculations and preliminary experimental results on its subcomponents.

This paper presents a fault tolerant distributed ATM switch architecture based on wavelength division multiplexing. The switching fabric consists of an all-optical ring shared memory (possibly remotely located) switch ports. Input buffering is used to resolve cell conflicts. A number of scheduling strategies are proposed to control cell transmissions within the distributed switch, with particular attention given to efficiently handling multicast traffic, i.e., tightly controlling the delay jitter of output copies generated by the same input multicast cell, while achieving overall high throughput. These strategies exploit separate input queues in order to alleviate the throughput limitations of input queued switches due to the head-of-the- line blocking phenomenon. A simulation-based performance analysis of the proposed architecture is presented, taking as performance indices both the cell transfer delay and the multicast cell jitter. Results show that good performances can be achieved for both unicast and multicast traffic with the proposed algorithm.

In this paper a novel low-cost method for realization of the upstream channel in optical subscriber loops is investigated, based on synchronous code-division multiplexing and block interleaving. To prove the performance of the proposed system concept the influence of different sequences and the combination with forward error correction is examined. Moreover, the implementation of a multi-user receiver is suggested which combines block interleaver and matched filter.

Starting from the Starring and the GIMS networks a new Interconnection Multihop Network called EXSTAR is presented. It has potentialities, in terms of number of users, modularity and performance much higher than Starring, GIMS and other multihop structures. Moreover it still offers a notable simplicity in routing strategies, giving rise to routing processors including only few all-optical gates.

PHOTON is one of the ACTS projects which aims at the development of selected concepts for the future transport network and at the implementation of its key functionalities in a field trial for demonstration of the feasibility and validation of the networking ideas. Within the project PHOTON the design of the all-optical nodes for the optical transport network will be demonstrated and verified in the PHOTON field trial called PHOTONET. In PHOTONET, a border crossing star network between Munich and Vienna via Passau will be implemented demonstrating transmission and cross- connection of optical frequency division multiplexed signals over already installed single mode fiber, spanning a distance of 524 km. The optical cross connect (OCC) builds the inner node of the network, connecting several FDM links (multichannel ports) and a number of single channel ports. The latter ones are used for adding local add/drop functionality to the OCC. The principal functions of an OCC are to perform all-optical cross-connecting, optical signal supervision, optical signal regeneration and add/drop functionality. The optical terminal multiplexer (OTMX) builds the interface between the client network and the optical transport network. The basic functions of the OTMX are the provision of the interface to the existing transport networks and to the novel leased optical channel service. The OCC and OTMX architectures are modular, so that any new requests for improvement of their functionality (as frequency conversion or fiber protection switching) can be easily achieved.

We propose two possibilities to combine multiple optical wavelengths with code division multiple access (CDMA) to achieve asynchronous access in diffuse IR-systems. A serial coding type which combines D-ary wavelength-shift keying with incoherent CDMA and a parallel coding type where the channels are distinguished by time/wavelength-matrices are investigated. We analyze the theoretical performance and show numerical results for different code families.

Two major drawbacks stand in the way of practical realization of scalable packet switched all-optical WDM networks. Beyond the obvious dependence on the number of wavelengths, these are the complexity of fast reconfigurable WDM crossconnects and the network wide synchronization. This paper presents a modular folded bus based architecture using photonic slot routing that circumvents the above drawbacks, leading to the potential realization of large all-optical networks based on extant optical technology.

During the last years EURESCOM has launched a set of projects in the area of TMN addressing the problems of pan- European broadband networks and services management. The X interfaces, which provide the means for co-operative management of different domains, are the emphasis in this context. Two such X interfaces are developed for the pan- European broadband SDH/ATM services: the Xcoop interfaces situated between two public management domains and the Xuser interface which is situated between a private and a public management domain. The Xcoop interfaces support the co- operations between the Public Network Operators in providing the global connectivities, whereas the Xuser offers a means of provisioning the connectivity to the customers by enabling the customer management entities in the private domains to subscribe for the service, to access and to manage the global connectivities or related resources. This paper presents the results of the EURESCOM project P408 in specifying, implementing and testing these X interfaces, and discusses the experiences obtained.

The importance of managing networks and services is finally being accepted by both operators/service providers and HW/SW manufacturers. Standards are thus coming for managing solutions based on any new emerging technology. However standards and commercial solutions have different level of completeness and performance depending on the related managed technology. Thus, being real systems often composed of a mix of different technologies, the quality of their overall management is limited by the less mature and effective single technology management system. Today broadband networks can be seen as a layered structure including ATM, SDH and WDM optical layers. While the management of SDH is quite mature and significant results are reached for ATM management, the management of the WDM optical layer is still in its infancy. Therefore the WDM layer management is a critical factor in the development of the overall broadband network management. The paper, after few considerations on general public network management issues, presents some solutions currently under study for the WDM optical layer management. Although the improvement of the weaker single technology management system surely improves the quality of the overall layered network management, this is just one step along the path for optimizing it. The objective is in fact the integration of the single layer management systems into a global one, avoiding duplications and improving efficiency and effectiveness. The paper presents at the end some considerations about this topic that is rapidly getting hot because of the potential economical benefits such as integration can offer.

Network management is a difficult task and becomes even more complex when involves the requirements of a high performance network as in the case of the ATM architecture. The work presented in this paper proposes the implementation of recently released ITU-T recommendations and investigates the usage of the TMN concepts for the management of ATM networks. Within this context, efforts were concentrated on the development of configuration and fault functions for the control of virtual channel and virtual path connections. More specifically, the work under development covers the monitoring and control of establishment and release of an end-to-end ATM connection, the allocation of corresponding VP/VC identifiers and the activation of the cell flow applied to the connection. Furthermore a testing mechanism through the usage of OAM cells was also implemented.

The introduction of the European Open Service Market will place greater emphasis on the design and development of services which can co-operate to provide end-users with integrated customizable end-to-end services. This is increasingly evident in the growth in sophistication of customer service requirements. This paper examines the trends and evidence which underlie the development of service management systems for such a market. The paper proposes a design approach which focuses on the inter-domain aspects of service management and presents the development of an example enterprise mode for management for tele- educational services.

ACTS Project AC080 MISA has embarked upon the task of realizing and validating via European field trials integrated end-to-end management of hybrid SDH and ATM networks in the framework of open network provision. This paper reflects the initial work of the project and gives an overview of the proposed MISA system architecture and initial design. We describe our understanding of the underlying enterprise model in the network management context, including the concept of the MISA Global Broadband Connectivity Management service. It supports Integrated Broadband Communication by defining an end-to-end broadband connection service in a multi-domain business environment. Its implementation by the MISA consortium within trials across Europe aims for an efficient management of network resources of the SDH and ATM infrastructure, considering optimum end-to-end quality of service and the needs of a number of telecommunication actors: customers, value-added service providers, and network providers.