SUMMARY The ever‐increasing share of the peer‐to‐peer (P2P) traffic flowing in the Internet has unleashed new challenges to the quality of service provisioning. Striving to accommodate the rise of P2P traffic or to curb its growth has led to many schemes being proposed: P2P caches, P2P filters, ALTO mechanisms and re‐ECN. In this paper, we propose a scheme named ‘UARA:textbfUser/Application‐aware RED‐based AQM’ which has a better perspective on the problem: UARA is proposed to be implemented at the edge routers providing real‐time near‐end‐user traffic shaping and congestion avoidance. UARA closes the loopholes exploited by the P2P traffic by bringing under control the P2P users who open and use numerous simultaneous connections. In congestion times, UARA monitors the flows of each user and caps the bandwidth used by ‘power users’ which leads to the fair usage of network resources. While doing so, UARA also prioritizes the real‐time traffic of each user, further enhancing the average user quality of experience (QoE). UARA hence centralizes three important functionalities at the edge routers: (1) congestion avoidance; (2) providing user fairness; (3) prioritizing real‐time traffic. The simulation results indicate that average user QoE is significantly improved in congestion times with UARA at the edge routers. Copyright © 2011 John Wiley & Sons, Ltd.

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Botnets have become platforms to launch distributed denialof-service attacks and coordinate massive e-mail spam campaigns, to name just a few of botnet-related nefarious activities. Apart from the wired networks, the increasingly Internetenabled cellular wireless networks are also vulnerable to botnet attacks; a situation which motivates a thorough study of botnet expansion and the mathematical models thereof. In this paper, we propose the following two Continuous-Time Markov Chain-based models for prediction of the botnet size in the initial phase of botnet lifecycle: SComF for the case of finite number of susceptible nodes (suitable for a botnet expanding in a closed environment such as an administrative domain, or a LAN) and SComI for the case of infinite number of susceptible nodes (suitable for a botnet expanding in the larger Internet). Having access to such models would enable security experts to have reliable size estimates and therefore be able to defend against an emerging botnet with adequate resources. We derive the probability distributions for both models and provide some numerical results as well as a simulation study accompanying the numerical analysis of the SComF model using the GTNetS network simulator.

This paper focuses on the transmission of real-time fax in IP networks. For this purpose, the best current practices, i.e., utilization of the Session Initiation Protocol (SIP) as the signaling protocol along with ITU-T T.38 recommendation, are adopted. Two traffic engineering measures: utilization of SIP contact header and DiffServ QoS architecture, are proposed to streamline the implementation of the real-time FoIP. Network simulation results show that the proposed architecture, compared to the "Best Effort" service, has much less transmission time and jitter, and packets received are in correct sequence. Moreover, SIP contact header reduces load on network's specialized resources. Therefore, this layout is a viable alternative for traditional PSTN fax.