Showing papers by "Franco Callegati published in 2003"

The European IST project DAVID: a viable approach toward optical packet switching

Abstract: In this paper, promising technologies and a network architecture are presented for future optical packet switched networks. The overall network concept is presented and the major choices are highlighted and compared with alternative solutions. Both long and shorter term approaches are considered, as well as both the wide-area network and multiple-area networks parts of the network. The results presented in this paper were developed in the frame of the research project DAVID (Data And Voice Integration over DWDM) project, funded by the European Commission through the IST-framework.

Optical burst and packet switching: node and network design, contention resolution and quality of service

Abstract: Future network should be able to efficiently serve packet-based networks, such as the Internet. In this paper, based on results from COST 266, we explore characteristics of optical burst switching (OBS) and optical packet switching (OPS). Both node design and metropolitan area network (MAN) are discussed. A unique joint comparative performance evaluation of contention resolution in OBS and OPS are presented, as well as methods of quality of service (QoS) differentiation in OBS/OPS networks, and their performance.

Optical burst and packet switching: node and network design, contention resolution and quality of service, Results from the study in COST 266

Abstract: Future network should be able to efficiently serve packet-based networks, such as the Internet. In this paper, based on results from COST 266, we explore characteristics of optical burst switching (OBS) and optical packet switching (OPS). Both node design and metropolitan area network (MAN) are discussed. A unique joint comparative performance evaluation of contention resolution in OBS and OPS are presented, as well as methods of quality of service (QoS) differentiation in OBS/OPS networks, and their performance.

Optical burst switching and optical packet switching

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 …

DWDM for QoS Management in Optical Packet Switches

Abstract: This paper addresses the problem of quality of service management in optical packet switching over DWDM. Asynchronous, variable length packets are considered and algorithms able to offer congestion resolution and quality of service differentiation are presented, with reference to both connectionless and connection oriented network scenarios. The paper aims at showing that it is possible to guarantee differentiation of the quality of service among traffic classes, with very little buffering requirements.