Gert Eilenberger

Design and technology aspects of VLSIs for ATM switches

A system concept based on a multipath self-routing switching principle and on an internal transfer mode using multislot cells is introduced. With the utilization of a shared buffer memory structure, this concept allows for a single-chip realization of the switching elements and fulfils important system requirements like fault tolerance, independence of the switch core from external data formats and traffic characteristics, and modular extendibility from small to very large systems. An example implementation of the concept with the resulting functional partitioning in boards and chips is given. Performance study results, as a basis for dimensioning, are also presented. The most important design aspects and a possible tool chain exploiting a hardware description language, logic simulator, and logic compiler are highlighted. >

Key building blocks for high-capacity WDM photonic transport networks

The objective of this paper is to give an overview of the different studies we have performed at the research level regarding the design and implementation of a photonic wavelength division multiplexing (WDM) layer providing transparent transport services to client layers (SONET/SDH, ATM, etc.). Such a network requires a number of enabling factors to be assessed in order to become a reality. Among these factors are the availability of high-capacity WDM transmission systems and efficient optical routing nodes based on mature technology, the design of robust networks optimizing the utilization of resources, and the development of a management system in accordance with presently applied standards for transport networks. We review our achievements in these different fields.

Hybrid burst/packet switching architectures from IP NOBEL

In spite of its long term promise, all-optical switching is still plagued by high cost, low efficiency when handling bursty data traffic, immature management and protection and poor output port contention resolution leading to heavy loss. Given the current situation, hybrid approaches that keep the best features of optics, reverting to the electrical plane when expedient, constitute sensible interim steps that can offer cost-effective solutions along the road to an eventual all-optical core. Two such approaches developed in the framework of the European IP project NOBEL are presented in this work. The first is a quite mature solution that extends present day concepts to achieve multiplexing gain while keeping all the management and restoration benefits of SDH. The other mimics early LANs in executing a distributed switching via its electrical control plane using two-way reservations, thus restricting its applicability to smaller domains. Combining the two leads to a system fulfilling most of todays requirements for Tb/s core networks.

System approach for a photonic multidimensional switching technique

A system concept for an optical switching fabric based on a principle using space, time, and frequency switching stages is described. The required asynchronous transfer mode (ATM) cell buffers for contention resolution, which are difficult to realize with optical techniques, are minimized by exploiting the wavelength domain, thus providing high capacity and optimum usage of technologies. The related key components, such as tunable sources and optical wavelength converters based on InP technologies and advanced space switching matrices based on polymeric nonlinear optical materials, are described, and basic characteristics are presented.<<ETX>>

Dynamic connection rearrangements in ATM switching networks

Two classes of ATM (asynchronous transfer mode) switching network architectures based on preset path routing and on statistical self-routing switching techniques are considered. They are evaluated in terms of their basic properties and their capabilities to cope with point-to-multipoint connection requirements. The principles of connection rearrangement techniques in an ATM environment are described and possible applications in both classes of switching network architectures are evaluated. A preset path routing switch can gain considerably in performance for all types of connections at the expense of excessive control effort. A statistical self-routing switch can have advantages for point-to-multipoint connections with moderate additional effort.<<ETX>>

Long term network architectures and scenarios based on optical burst/packet switching

IP based traffic is seen as the convergence protocol for all future services and is already dominating todays networks. From the current situation with circuit switched SDH/SONET and packet switched IP backbones, an evolution is described towards long term optical transport network architectures featuring multi-layer transport with a novel Layer 2 transport service based on optical and opto-electronic burst/packet techniques as convergence layer providing the flexibility, scalability, reliability and Quality-of-Service to support all future higher layer services optimizing both CAPEX and OPEX. The operation of such a network will be mostly automatic supported by an integrated Control Plane on the basis of GMPLS protocols covering Layer 1, Layer 2 and Layer 3 (vertical integration of WDM, SDH, Ethernet, Bursts, IP etc.) and providing end-to-end control over various administrative and vendor domains (horizontal integration). The introduction of a new L2 transport service and its integration into a multi-layer Control Plane will be a long term evolutionary process also involving the necessary steps in the evolution of current standards. A few examples of network architectures and solutions are described together with dimensioning and control aspects and their relation to a roadmap for the introduction of optical burst/packet networks.

All-optical routing of non-binary signals in WDM access networks

All-optical routing of non-binary signals in WDM access networks offers flexibility and survivability. This concept has been verified experimentally, exploiting active and passive optical routing components for QAM signals typical in the access regime.

The Integrated Project NOBEL

This paper presents the main results achieved by the IST Integrated Project NOBEL in its first phase and the objectives of its second phase.

Multi-Layer Recovery Enabled with End-to-End Signaling

Within GMPLS framework, the signaling protocol Resource reSerVation Protocol with Traffic Engineering extensions (RSVP-TE) is extended to support the requirements of an Automated Switched Optical Network architecture. This paper presents the extensions of the end-to-end connection services in an overlay network built on two control planes. RSVP-TE protocol extensions are first described between an IP/MPLS router and a SDH/GMPLS core optical cross-connect, defining GMPLS-UNI. Dimensioning of three scenarios proving the benefits of GMPLS-UNI is discussed.

Network element and network level parameters for the management of optical networks

From the functional architecture of optical network elements, parameters for fault and performance management are proposed for network element-level management. At the network level, some parameters are considered to assess the performance of end-to-end channel trails.