Giovanni Schembra

Learn 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 the last few years an increasing amount of attention has been paid to technologies for the transmission of voice over IP (VoIP). At present, the UDP transport protocol is used to provide this service. However, when the same bottleneck link is shared with TCP flows, and in the presence of a high network load and congestion, UDP sources capture most of the(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)
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)
Multimode coders are able to exploit the different characteristics of the speech waveform and to take into account the different peculiarities of background noise, thus allowing improvements in both signal reconstruction and network offered load. In this context the Variable Rate CELP (VR-CELP) coding, that is, a multimode VBR coding based on the Code(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)
Improving energy efficiency in Internet equipments is becoming an increasingly important research topic. In this paper, we discuss the lesson gained by experimenting a power management mechanism aimed at reducing the power consumption while guaranteeing the Quality of Service (QoS). To this purpose, we drive the clock frequency of an open flexible and(More)