Francesco Vacirca

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In this paper, we investigate interactions between TCP and wireless hybrid FEC/ARQ schemes. The aim is to understand what is the best configuration of the wireless link protocol in order to guarantee TCP performance and channel efficiency. Interactions between TCP and different link layer mechanisms are evaluated by means of an analytic model that(More)
In this paper we present some observations about TCP RTT as captured in the live traffic of an operational GPRS/UMTS network. RTT samples are extracted from traces collected by passive monitoring the Gn interfaces of one of the major providers in Austria, EU. We compare results for GPRS and UMTS, and expose some methodological issues involved in performing(More)
In this paper we present the results of experiments carried out in an infra-structured 802.11b WLAN comprising a single Access Point (AP) and a number of user terminals. The aim of this work is twofold: by the one hand, we validate well-known “TCP (UDP) over 802.11” analytic models by means of experimental results; by the other hand, we focus our analysis(More)
This paper proposes an algorithm to identify TCP spurious retransmission timeouts by post processing of packet traces monitored in operational networks. The operational principles of the algorithm and the assumptions behind its design are explained in detail as well as the situations in which the algorithm is prone to inaccuracies. By extensive measurements(More)
In this work we address the problem of inferring the presence of a bottleneck from passive measurement in the UMTS core network. The study is based on one month of packet traces collected in the core network of mobilkom austria AG & Co KG, the leading mobile telecommunications provider in Austria, EU. During the measurement period a bottleneck link in(More)
In recent years, several new TCP congestion control algorithms have been proposed to speed up the TCP over very fast networks. All these algorithms propose their own modifications of the increasing/decreasing phases of classic Reno/NewReno TCP. On the other hand, all of them preserve the self-clocking mechanism, which is a fundamental part of the classic(More)
A single TCP connection with a time varying capacity bottleneck link is considered. The bottleneck capacity varies arbitrarily and independently of the TCP connection traffic; it aims at reproducing typical situations where capacity is modulated by exogenous process, such as wireless channel with link adaptation or bursty channels. The key point is to(More)
The objective of this study was to estimate heritabilities and genetic correlations between milk-release parameters, somatic cell score, milk yield, and udder functional traits in the Italian Brown Swiss population. Data were available from 37,511 cows over a span of 12 yr (1997-2008) from 1,592 herds. Milking flows were recorded for each individual once(More)
TCP congestion control has been designed to ensure Internet stability along with fair and efficient allocation of the network bandwidth. With the spreading of high-speed and long-distance networks, the standard TCP congestion control algorithm showed some limitations in exploiting full bandwidth utilization. During the last few years, many new congestion(More)