Showing papers by "Franco Callegati published in 2001"
TL;DR: Two approximate analytical models are presented that can be used both for analysis and engineering of the optical buffer and in particular to dimension the buffer time unit in an way that is optimal with respect to packet loss probability.
Abstract: This paper addresses the problem of dimensioning buffers realized by means of fiber delay lines in optical routers able to switch packets that have variable length and are sent asynchronously on the optical links. The optical buffer is analyzed focusing on the different behavior of a delay buffer and an electronic memory. The role of the time unit of the fiber delay lines is discussed, showing that it is a crucial parameter to determine the queuing performance. The paper presents two approximate analytical models that can be used both for analysis and engineering of the optical buffer and in particular to dimension the buffer time unit in an way that is optimal with respect to packet loss probability. The first model is based on an infinite queuing approximation. It is not very accurate and is valid for a limited set of values of the traffic load, but is extremely simple. The second model is based on a finite queuing approximation. It is more complex but more accurate and is valid for any value of traffic load. The accuracy of the models is compared with simulation and their range of applicability purposes is discussed.
46 citations
11 Jun 2001
TL;DR: It is shown that the buffering performance strongly depends on the choice of the delay unit of the FDL's and that the algorithm aiming at reducing the artificial increase in the load due to the discrete time scale of the buffer gives best performance.
Abstract: This paper addresses the problem of buffering performance optimization for asynchronous, variable length packets in a DWDM optical network. In the case of a multiplexing scheme that shares the wavelength resource among all packets regardless the connection they belong to, the problem of defining a wavelength allocation algorithm arises. Wavelength allocation has to be merged with delay allocation in buffers realized by means of fiber delay lines (FDLs). This paper proposes several allocation algorithms and compares their performance. It shows that the buffering performance strongly depends on the choice of the delay unit of the FDL's and that the algorithm aiming at reducing the artificial increase in the load due to the discrete time scale of the buffer gives best performance.
26 citations
TL;DR: The main results show the effectiveness of dynamic assignment with respect to static one and show that the connection configuration can be exploited for performance enhancement.
Abstract: This paper deals with the problem of connection to wavelength assignment in an MPLS optical packet switched network with DWDM links. The need to adopt dynamic allocation of connections to wavelengths is outlined to avoid congestion and dynamic wavelength assignment algorithms are proposed. The main results show the effectiveness of dynamic assignment with respect to static one and show that the connection configuration can be exploited for performance enhancement
6 citations
30 Sep 2001
TL;DR: The paper proposes an algorithm for wavelength sharing that aims at minimizing congestion and limit queuing requirements that is compatible with the current MPLS packet switched network.
Abstract: This paper deals with the problem of an MPLS packet switched network with DWDM links and addresses the issue of congestion avoidance by means of wavelength sharing among MPLS connections. The paper proposes an algorithm for wavelength sharing that aims at minimizing congestion and limit queuing requirements.
4 citations
01 Jan 2001
TL;DR: This paper addresses the problem of building optical packet switches able to effectively cope with variable length packet traffic, such as IP traffic by proposing an architecture equipped with a multistage fiber delay lines based buffer.
Abstract: This paper addresses the problem of building optical packet switches able to effectively cope with variable length packet traffic, such as IP traffic. Aswit ching architecture equipped with a multistage fiber delay lines based buffer is presented. The aim is to realize a buffer with fine granularity and long delay with an architecture of limited complexity. QoS mechanisms are proposed to support service differentiation by exploiting the wavelength resource and are evaluated by simulation.
3 citations