Giovanni Schembra

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Promoting the evolution of the Internet from a simple data network to a true multiservice network today constitutes a challenging task. To this end, the Internet Engineering Task Force (IETF) has set up the Integrated Services (Intserv) and Differentiated Services (DiffServ) Working Groups, with the goal of defining a next-generation Internet, in which(More)
Power consumption of the Information and Communication Technology sector (ICT) has recently become a key challenge. In particular, actions to improve energy-efficiency of Internet Service Providers (ISPs) are becoming imperative. To this purpose, in this paper we focus on reducing the power consumption of access nodes in an ISP network, by controlling the(More)
In this paper an accurate and treatable Markov-based model for MPEG video traffic is proposed. Before reaching a definition of the model, a large number of MPEG video sequences are analyzed and their statistical characteristics are highlighted. Besides the well-known autocorrelation function, testifying the pseudo-periodicity of the sequence in the short(More)
In this paper a multimedia source is modeled as an arrival process defined as the superposition of heterogeneous correlated arrival processes, each of which models one monomedia source. To this purpose each monomedia source is modeled as an ON-OFF process where the transition rates are functions of the states of the other monomedia sources. Auto-and(More)
In this paper a finite-buffer discrete-time approach is presented in order to analyze the performance of a multiplexer loaded by N multimedia sources. For this purpose the emission process of each multimedia source is defined as the superposition of heterogeneous correlated emission processes, each of which models one monomedia source as a Switched Batch(More)
—Guarantees of quality-of-service (QoS) in the real-time transmission of stored video on the Internet is a challenging task for the success of many video on demand (VoD) applications. Two QoS classes have been specified by the IETF Integrated Services (intserv) Working Group: Guaranteed Services and Controlled-Load Services. For both of them, it is(More)
Design methodologies for TCP/IP based networks is one of the most challenging topic in research on telecommunications networks. The main difficulty consists in modeling congestion control mechanisms because it involves feedback from the network. In this perspective, in this paper we develop an accurate analytical framework for networked TCP applications(More)
In this paper the skew affecting a multimedia traffic stream when N multimedia streams are mixed in an ATM multiplexer is evaluated. To this purpose a multimedia source is modeled by an arrival process defined as the superposition of heterogeneous correlated arrival processes, each of which models one monomedia source by means of an MMBP process whose(More)
In this paper we propose an analytical model for the study of two different routing strategies in an ATM network supporting multimedia traffic flow: the Multimedia Virtual Circuit (MVC) and the Independent Virtual Circuit (IVC). The first strategy consists of assigning a single virtual channel to all the monomedia streams which make up the multimedia flows;(More)