Piet Van Mieghem

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The influence of the network characteristics on the virus spread is analyzed in a new--the <i>N</i>-intertwined Markov chain--model, whose only approximation lies in the application of mean field theory. The mean field approximation is quantified in detail. The <i>N</i>-intertwined model has been compared with the exact 2<sup><i>N</i></sup>-state Markov(More)
Romualdo Pastor-Satorras, Claudio Castellano, 3 Piet Van Mieghem, and Alessandro Vespignani 6 Departament de F́ısica i Enginyeria Nuclear, Universitat Politècnica de Catalunya, Campus Nord B4, 08034 Barcelona, Spain Istituto dei Sistemi Complessi (ISC-CNR), via dei Taurini 19, I-00185 Roma, Italy Dipartimento di Fisica, “Sapienza” Università di Roma, P.le(More)
The underlying concepts of an exact QoS routing algorithm are explained. We show that these four concepts, namely 1) nonlinear definition of the path length; 2) a &#60;i>k&#60;/i>-shortest path approach; 3) nondominance; and 4) look-ahead, are fundamental building blocks of a multiconstrained routing algorithm. The main reasons to consider exact(More)
Based on SAMCRA, an improved and exact version of our QoS routing algorithm TAMCRA, we have investigated QoS routing in a hop-by-hop manner because it forms the basis of IP networking as e.g. in OSPF. In particular, we studied ‘hop-by-hop destination based only’ (HbHDBO) QoS routing that ignores the source and previous path history (as in current IP(More)
$EVWUDFW Routing with more than one additive constraints is known to be an NP-complete problem, and hence considered as intractable. We present a new QoS routing algorithm, called Tunable Accuracy Multiple Constraints Routing algorithm (TAMCRA), which solves the problem in a fast and accurate way. Although the current internet is a best-effort network,(More)
Quality of Service (QoS) provisioning generally assumes more than one QoS measure which implies that QoS routing can be categorized as an instance of routing subject to multiple constraints. The ATMforum PNNI standard, in particular the routing part, belongs to the most promising, future-save, QoS-aware, dynamical and hierarchical routing protocols. The(More)
Multicast routing algorithms that are capable of providing quality of service (QoS) to its members will play an important role in future communications networks. This paper discusses some fundamental properties of multicast routing subject to multiple QoS requirements. We will show that guaranteeing QoS and optimizing resource utilization are conflicting(More)
Serious epidemics, both in cyber space as well as in our real world, are expected to occur with high probability, which justifies investigations in virus spread models in (contact) networks. The N-intertwined virus spread model of the SIS-type is introduced as a promising and analytically tractable model of which the steady-state behavior is fairly(More)