In this paper, we formulate an analytical model to characterize the spread of malware in decentralized, Gnutella type peer-to-peer (P2P) networks and study the dynamics associated with the spread of malware. Using a compartmental model, we derive the system parameters or network conditions under which the P2P network may reach a malware free equilibrium. The model also evaluates the effect of control strategies like node quarantine on stifling the spread of malware. The model is then extended to consider the impact of P2P networks on the malware spread in networks of smart cell phones.

The residual power levels of the nodes in a wireless sensor network determine its important performance metrics like the network lifetime, coverage, and connectivity. In this paper, we present a general framework to model the availability of power at sensor nodes as a function of time, based on models for population dynamics in biological studies. Models are developed for sensors with and without battery recharging and expressions are derived for the network lifetime as well as the distribution and moments of random variables describing the number of sensors with different levels of residual energy as a function of time. The model is also extended to the case where new sensors are periodically added to the network to substitute older sensors that have expended their energy. Finally, the effect of the packet arrival rates and a sensor's geographical location are modeled. Simulation results to verify the accuracy of the proposed models are presented.

This paper presents a queuing model to evaluate the latency associated with file transfers or replications in peer-to-peer (P2P) computer systems. The main contribution of this paper is a modeling framework for the peers that accounts for the file size distribution, the search time, load distribution at peers, and number of concurrent downloads allowed by a peer. We propose a queuing model that models the nodes or peers in such systems as M/G/1/K processor sharing queues. The model is extended to account for peers which alternate between online and offline states. The proposed queuing model for the peers is combined with a single class open queuing network for the routers interconnecting the peers to obtain the overall file transfer latency. We also show that in scenarios with multipart downloads from different peers, a rate proportional allocation strategy minimizes the download times.

A number of important characteristics of wireless sensor networks such as the lifetime, connectivity and coverage are determined the residual power levels of the nodes in the network. This paper presents a general framework for modeling the availability of power at sensor nodes as a function of time. Models are developed for sensors with and without battery recharging and expressions are derived for the network lifetime as well as the distribution and moments of random variables describing the number of sensors with different levels of residual energy as a function of time. Finally, the effect of the packet arrival rates and a sensor's geographical location are modeled.

Recent outbreaks of virus and worm attacks targeted at cell phones have bought to the forefront the seriousness of the security threat to this increasingly popular means of communication. In this paper, we develop an analytic framework for modeling the dynamics of malware propagation in networks of mobile smart phones. We then characterize the conditions under which the network may reach a malware free equilibrium and derive the necessary conditions for its global asymptotic stability. The model accounts for malware transfers through a number of communication paradigms including the Internet, the telephone network, Bluetooth and WiFi in addition to accounting for the mobility of cell phones and the impact of the heterogeneous environments they pass through on the malware dynamics.

Recent outbreaks of virus and worm attacks targeted at cell phones have have bought to the forefront the seriousness of the security threat to this increasingly popular means of communication. The ability of smart cell phones to communicate through both the Internet and the telecom networks along with the presence of a number of communication interfaces makes them vulnerable to attacks from a number of sources which can then propagate at extremely fast rates. In this paper we develop an analytic framework for modeling the dynamics of malware propagation in networks of smart phones that specifically accounts for the mobile nature of these devices. We also characterize the conditions under which the network may reach a malware free equilibrium and derive the necessary conditions for its global asymptotic stability. The model accounts for malware transfers through the Internet and peer to peer networks, through the telephone network and through Bluetooth and WLAN interfaces.

A key emerging and popular communication paradigm, primarily employed for information dissemination, is peer-to-peer (P2P) networking. In this paper, we model the spread of malware in decentralized, Gnutella type of peer-to-peer networks. Our study reveals that the existing bound on the spectral radius governing the possibility of an epidemic outbreak needs to be revised in the context of a P2P network. We formulate an analytical model that emulates the mechanics of a decentralized Gnutella type of peer network and study the spread of malware on such networks. We show analytically, that a framework which does not incorporate the behavioral characteristics of peers ends up over estimating the epidemic threshold metric, R0. This in turn results in false positives, an undesirable feature. We also characterize the conditions under which the network may reach a malware free equilibrium and validate our theoretical results with numerical simulations

This paper presents an analytic framework to evaluate the performance of peer to peer (P2P) networks. Using the time to download or replicate an arbitrary file as the metric, we present a model which accurately captures the impact of various network and peer level characteristics on the performance of a P2P network. We propose a queueing model which evaluates the delays in the routers using a single class open queueing network and the peers as M/G/1/K processor sharing queues. The framework takes into account the underlying physical network topology and arbitrary file sizes, the search time, load distribution at peers and number of concurrent downloads allowed by a peer. The model has been validated using extensive simulations with campus level, power law AS level and ISP level topologies. The paper also describes the impact of various parameters associated with the network and peers including external traffic rates, service variability, file popularity etc. on the download times. We also show that in scenarios with multi-part downloads from different peers, a rate proportional allocation strategy minimizes the download times.