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Ch. Gauger

Bio: Ch. Gauger is an academic researcher from Budapest University of Technology and Economics. The author has contributed to research in topics: Optical burst switching & Optical performance monitoring. The author has an hindex of 1, co-authored 3 publications receiving 7 citations.

Papers
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Book Chapter
01 Jan 2003
TL;DR: Optical Packet Switching and Optical Burst Switching come into play, with the goal of reducing delays and improving the utilisation of the network's resources through statistical multiplexing.
Abstract: Most existing wide area telecommunication networks (WAN) have an SDH based, electronically circuit switched transport core. Connection setup or tear down may require days or weeks and multiplexing/demultiplexing always require complex optical/electro/optical (O/E/O) conversions. Nowadays, the operators and vendors are working on an optical control plane, which should control setup and tear down of connections. Work on automatically switched optical network (ASON) and generalised multi-protocol label switching (GMPLS) takes place within ITU and IETF, respectively. Resulting optically circuit switched (OCS) networks can offer explicit transfer guarantees, since circuit establishments are confirmed. However, this generates a delay equal at least to the round-trip time, typically several ms. Even though OCS networks will offer more flexibility than today's solution, the access to the optical bandwidth will still be provided with fibre/wavelength granularity. Future networks should be able to serve a client layer that includes packet-based networks, such as the Internet, which may have a highly dynamic connection pattern with a significant portion of bursty traffic between the communicating pairs. In this case, OCS transport may not be flexible enough. It would require over-dimensioning of the number of connections and of the bandwidth reservation of each connection, to avoid excessive delay and extensive buffering at the ingress router. Here is when Optical Packet Switching (OPS) and Optical Burst Switching (OBS) come into play, with the goal of reducing delays and improving the utilisation of the network's resources through statistical multiplexing. This comes at the expense of not being able to offer explicit transfer guarantees. However, suitable node design and proper dimensioning of network resources may enable support of most services over the same network. OPS and OBS logical performance in relation to contention resolution and quality of service (QoS) differentiation will be discussed in 4.3 and 4.4. Moreover, hybrid schemes are possible where OPS and OBS share the WDM layer with an OCS scheme, serving applications with the need for explicit transfer guarantees. Europe has been very active in OPS research, especially through projects like RACE ATMOS [1], ACTS KEOPS [2], IST DAVID [3], IST STOLAS [4] and COST 266. OBS was proposed very recently [5], but different research groups in Europe have already made significant contributions to this field, as later sections in this chapter show. Inevitably, there are some differences in terminology within the research community; we here explicitly describe some concepts and terms used in this chapter. Both optical packet …

6 citations

01 Jan 2002
TL;DR: This paper discusses the evolution of optical systems starting from WDM links to Optical Packet Switching Networks via some stages as Switched Optical Networks, Multilayer Networks with either traffic or wavelength grooming, Optical VPNs and Optical Burst Switching.
Abstract: This paper discusses the evolution of optical systems starting from WDM links to Optical Packet Switching Networks via some stages as Switched Optical Networks, Multilayer Networks with either traffic or wavelength grooming, Optical VPNs and Optical Burst Switching. We discuss the advantages and drawbacks of certain approaches since the future developments of optical networking technology might influence this evolution. We also draw our near-term and long-term visions of optical networking.

1 citations

Proceedings ArticleDOI
07 Aug 2002
TL;DR: In this article, the authors discuss the evolution of optical systems starting from WDM links to optical packet switching networks via some stages such as switched optical networks, multilayer networks with either traffic or wavelength grooming, optical VPN and optical burst switching.
Abstract: This paper discusses the evolution of optical systems starting from WDM links to optical packet switching networks via some stages such as switched optical networks, multilayer networks with either traffic or wavelength grooming, optical VPN and optical burst switching. We discuss the advantages and drawbacks of certain approaches since the future developments of optical networking technology might influence this evolution. We also draw our near-term and long-term visions of optical networking.

1 citations


Cited by
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Journal Article
TL;DR: A novel non-conventional approach to the future optical and wireless hybrid transport network that is capable of supporting the dominating kinds of traffic, i.e., voice/real-time, wireless and packet traffic, in a single transport network.
Abstract: We present a novel non-conventional approach to the future optical and wireless hybrid transport network that is capable of supporting the dominating kinds of traffic, i.e., voice/real-time, wireless and packet traffic, in a single transport network. The proposed model combines different technologies as connection and connectionless networks, optical cable and wireless (microwave/millimetre wave or optical wireless) and it is suitable for a variety of purposes and services in order to achieve global broadband networking features. Our new networking model contains an extension to the wireless world in order to achieve mobility and personalisation of the connection. It consists of an upgrade of real-time traffic with a microwave modulated optical wave, in order to carry out conventional mobile wireless via optical fibres though long distances and without a significant distortion. The whole available bandwidth can be fully exploited in the hybrid network. In the IP part of the network, quality of service can be differentiated for various classes of packets and network reliability/survivability can be categorised for the whole hybrid network. This substitutes the complete and revolutionary shifting to packet traffic, that many promote, with smooth evolutionary upgrades.

10 citations

Proceedings ArticleDOI
04 Jul 2004
TL;DR: In this article, the authors present a non-conventional approach to the future optical and wireless hybrid transport network that is capable of supporting the dominating kinds of traffic, i.e., voice/real-time, wireless and packet traffic, in a single transport network.
Abstract: We present a novel non-conventional approach to the future optical and wireless hybrid transport network that is capable of supporting the dominating kinds of traffic, i.e., voice/real-time, wireless and packet traffic, in a single transport network. The proposed model combines different technologies as connection and connectionless networks, optical cable and wireless (microwave/millimetre wave or optical wireless) and it is suitable for a variety of purposes and services in order to achieve global broadband networking features. Our new networking model contains an extension to the wireless world in order to achieve mobility and personalisation of the connection. It consists of an upgrade of real-time traffic with a microwave modulated optical wave, in order to carry out conventional mobile wireless via optical fibres though long distances and without a significant distortion. The whole available bandwidth can be fully exploited in the hybrid network. In the IP part of the network, quality of service can be differentiated for various classes of packets and network reliability/survivability can be categorised for the whole hybrid network. This substitutes the complete and revolutionary shifting to packet traffic, that many promote, with smooth evolutionary upgrades.

10 citations

Dissertation
14 Feb 2008
TL;DR: The concept of E-OBS as mentioned in this paper was introduced by the xarxes de commutacio de rafegues optiques (OBS) as a solution to the imparable popularitzacio d'Internet i del seu us per a totus d'aplicacions.
Abstract: L'evolucio de les xarxes publiques de transport de dades destaca per el continu augment de la demanda de trafic a la que estan sotmeses. La causa es la imparable popularitzacio d'Internet i del seu us per a tot tipus d'aplicacions. Les xarxes de commutacio de rafegues optiques (OBS: Optical Bursts Switching) son una solucio extraordinariament prometedora per la proxima generacio de xarxes, tant per la flexibilitat que ofereixen com per el seu alt rendiment fruit de l'explotacio de la multiplexacio estadistica en el domini optic.Aquesta tesi presenta l'analisi, modelitzacio i avaluacio de les xarxes de commutacio de rafegues optiques basades en l'emulacio del temps de compensacio (emulated offset time: E-OBS). El concepte d'E-OBS defineix una arquitectura de xarxa OBS per al transportar i commutar rafegues optiques en una xarxa troncal en la que, al contrari de l'arquitectura convencional (C-OBS) en la que el temps de compensacio s'introdueix des dels nodes d'acces, el temps de compensacio s'introdueix en cadascun dels nodes de la xarxa per mitja d'un retardador de fibra addicional. L'arquitectura E-OBS permet superar algunes de les desavantatges inherents a arquitectures C-OBS, pero la seva gran virtut es la compatibilitat amb les xarxes de commutacio de circuits optics (OCS: Optical Circuit Switching) actuals i les futures xarxes de commutacio de paquets optics (OPS: Optical Packet Switching), de manera que les xarxes OBS basades en una arquitectura E-OBS) poden facilitat enormement la transicio de unes a les altres.A ala vista dels principals requeriments de disseny de les xarxes OBS, que son la resolucio de contencions en el domini optic, la provisio de qualitat de servei (QoS) i l'optim encaminament de les rafegues per tal de minimitzar la congestio de la xarxa, . en aquesta tesi es proposa un disseny de l'arquitectura E-OBS basada en (i) un metode viable per a la provisio del temps de compensacio, (ii) una qualitat alta global de servei, i (iii) un mecanisme d'encaminament que minimitzi congestio de xarxa.- La primera part d'aquesta tesi proporciona la informacio documental necessaria per al disseny d'E-OBS.- La segona part se centra en l'estudi de la funcionalitat i viabilitat de l'arquitectura E-OBS. S'introdueixen els principis d'operacio d'E-OBS i s'identifiquen els principals esculls que presenten les arquitectures C-OBS i que deixen de ser-ho en una arquitectura E-OBS. Alguns d'aquests esculls son la dificultat d'utilitzar un algorisme d'encaminament amb rutes alternatives, la complexitat dels algoritmes de reserva de recursos i la seva falta d'equitat, la complexitat en la provisio de la QoS, etc. En aquesta segona part es constata que l'arquitectura E-OBS redueix la complexitat dels de reserva de recursos i es verifica la viabilitat d'operacio i de funcionament de la provisio del tremps de compensacio en aquesta arquitectura a partir de figures de comportament obtingudes amb retardadors de fibra comercialment disponibles.- La tercera part encara el problema de la provisio de la QoS. Primer s'hi revisen els conceptes basics de QoS aixi com els mecanismes de tractament de la QoS per a xarxes OBS fent-ne una comparacio qualitativa i de rendiment de tots ells. Com a resultat s'obte que el mecanisme que presenta un millor comportament es el d'avortament de la transmissio de les rafegues de mes baixa prioritat quan aquestes col·lisionen amb una de prioritat mes alta (es l'anomenat Burst Preemption mechanism), el qual en alguns casos presenta un problema de senyalitzacio innecessaria. Aquesta tercera part es conclou amb la proposta d'un mecanisme de finestra a afegir al esquema de Burst Preemption que nomes funciona sobre una arquitectura E-OBS i que soluciona aquest problema.- En la quarta part s'afronta el problema de l'encaminament en xarxes OBS. S'estudia el comportament dels algoritmes d'encaminament adaptatius, els aillats amb rutes alternatives i els multicami distribuits, sobre xarxes E-OBS. A la vista dels resultats no massa satisfactoris que s'obtenen, es planteja una solucio alternativa que es basa en model d'optimitzacio no lineal. Es formulen i resolen dos models d'optimitzacio per als algoritmes encaminament de font multicami que redueixen notablement la congestio en les xarxes OBS.Finalment, aquesta tesi conclou que l'arquitectura E-OBS es factible, que es mes eficient que la C-OBS, que proveeix eficacment QoS, i que es capac d'operar amb diverses estrategies d'encaminament i de reduir eficacment la congestio de xarxa.

9 citations

DissertationDOI
01 Jan 2003
TL;DR: The systematical investigation of different protection schemes for photonic networks and the development of their efficient planning methods and the impact of uncertainties in the planning-process and the lack of knowledge of the exact traffic pattern on the required capacity is studied.
Abstract: The topic of this thesis is the systematical investigation of different protection schemes for photonic networks and the development of their efficient planning methods. Due to the high aggregation of large traffic streams, protection against losses is of central importance. The direct routing of a light path results in an optical path layer (OPL). Efficient protection schemes apply directly to the OPL. As a comparison criterion between the protection schemes, the figure of the total required capacity for the network with respect to working and protection traffic is used. After a short introduction and motivation for the investigation at hand, important methods and terms for the network planning process are explained by illustrating the routing and wavelength assignment of light paths. It follows a description of the Pan-European networks which have been used for the comparison. First, protection schemes for mesh networks are considered. Such networks are based on optical cross connects (OXC) and enable the use of very flexible routing schemes. Span and path based methods for dedicated and shared protection have been investigated. For the case of dedicated protection, it is possible to find optimal solutions with simple and exact methods by the separation into sub-problems. For shared protection, a novel, unified integer linear programming (ILP) formulation has been used. For networks with wavelength conversion (virtual wavelength path, VWP), the corresponding system of equations may be solved directly. For larger networks or in the case where a light path uses the same wavelength throughout the whole network (wavelength path, WP), heuristics are required to solve the problem which reduce the complexity significantly. Corresponding approaches for shared path protection and protection with so called p-cycles are developed. Ring structures depend on simple optical add-drop multiplexers (OADM) and are simpler to realize than mesh networks from a technological point of view. On the other hand, the planning of multi-ring-networks with several interweaved rings is very complex. It is shown that an effective graph for ring-networks with dedicated protection rings (DPRing) and shared protection rings (SPRing) can be developed. For DPRing-networks, this allows to deduce an optimal ring-coverage. For SPRing-networks, the ring-identification may be formulated as an ILP-problem. For this case, a novel method for the ring-routing and -dimensioning based on the effective graph is proposed. This method has been used for the iterative ring-identification. Finally, the impact of uncertainties in the planning-process and the lack of knowledge of the exact traffic pattern on the required capacity is studied. A summary and outlook for further research work concludes the thesis.

2 citations