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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 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(More)
— In this paper we investigate the interaction between TCP and wireless ARQ mechanisms. The aim is to understand what is the best reliability degree of the wireless link in order to guarantee TCP performance. For this purpose, we first develop a Markov model for a selective repeat ARQ protocol, widely used in the current wireless environments. Secondly, we(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)
— Wireless data is deemed as a major booster of next generation wireless networks. In this context, the support of Internet applications based on the TCP still presents several open issues. The aim of this work is to evaluate the performance of TCP data transfer over the UMTS TD-CDMA air interface, by means of a rather detailed simulation model. The(More)
Adaptive packet scheduling for wireless data access systems, including channel state information based algorithms, is a quite well established topic. We develop here an original framework to define such an algorithm in a recon-figurable context, i.e. with the ability to exploit heterogeneous communication environments. The focus is to define platform(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)