Marwan Abu-Amara

Optimal asynchronous agreement and leader election algorithm for complete networks with Byzantine faulty links

SummaryWe consider agreement and leader election on asynchronous complete networks when the processors are reliable, but some of the channels are subject to failure. Fischer, Lynch, and Paterson have already shown that no deterministic algorithm can solve the agreement problem on asynchronous networks if any processor fails during the execution of the algorithm. Therefore, we consider only channel failures. The type of channel failure we consider in this paper is Byzantine failure, that is, channels fail by altering messages, sending false information, forging messages, losing messages at will, and so on. There are no restrictions on the behavior of a faulty channel. Therefore, a faulty channel may act as an adversary who forges messages on purpose to prevent the successful completion of the algorithm. Because we assume an asynchronous network, the channel delays are arbitrary. Thus, the faulty channels may not be detectable unless, for example, the faulty channels cause garbage to be sent. We present the first known agreement and leader election algorithm for asynchronous complete networks in which the processors are reliable but some channels may be Byzantine faulty. The algorithm can tolerate up to

A heuristics based approach for cellular mobile network planning

\left[ {\frac{{n - 2}}{2}} \right]

A combined solution for the Internet access denial caused by malicious Internet service providers

faulty channels, where n is the number of processors in the network. We show that the bound on the number of faulty channels is optimal. When the processors terminate their corresponding algorithms, all the processors in the network will have the same correct vector, where the vector contains the private values of all the processors.

Wireless sensor network implementation for mobile patient

The 3rd Generation Partnership Project (3GPP) has adopted an interworking architecture between Universal Mobile Telecommunication System (UMTS) and Wireless Local Area Networks (WLANs). This architecture imposes a set of security requirements on subscribers connecting from within interworked WLANs to be able to access their 3G home packet-switched services. Providing seamless handoff and session continuity of ongoing communication is a critical task in UMTS/WLAN integrated networks. However, the 3GPP does not specify how mobility can be supported. This paper provides a performance evaluation for the three candidate solutions: Mobile IP (MIP), Session Initiation Protocol (SIP), and mobile Stream Control Transmission Protocol (mSCTP) that may be used to provide session continuity in the integrated network. The vertical handoff delay figure is analyzed using simulations for different WLAN speeds and its major components due to the involved signaling procedures are quantified. The results are derived from our developed OPNET based simulation model that accounts for the detailed prescribed signaling procedures as per the related standards and Request for Comments (RFCs) documents, and the main network entities in the adopted architecture. The presented analysis provides insight into the potential performance bottlenecks in the integrated network. Major findings of the work show that the security related signaling and the signaling pertaining to obtaining a new Internet Protocol (IP) address, each contribute about 40% of the total delay for all the three solutions. Enhancements targeting these procedures will help reduce the overall delay while supporting seamless handoff between the two networks.

Dynamic peer-to-peer (P2P) solution to counter malicious higher Domain Name System (DNS) nameservers

Designing and planning of the switching, signaling and support network is a fairly complex process in cellular mobile network. In this paper, the problem of assigning cells to switches in cellular mobile network, which is considered a planning problem, is addressed. The cell to switch assignment problem which falls under the category of the Quadratic Assignment Problem (QAP) is a proven NP--hard problem. Further, the problem is modeled to include an additional constraint in the formulation. The additional constraint is of the maximum number of switch ports that are used for a cells Base Station Transceiver System (BTS) connectivity to the switch. The addition of the constraint on the number of ports on a switch has immense practical significance. This paper presents a non--deterministic heuristic based on Simulated Evolution (SimE) iterative algorithm to provide solutions. The methods adopted in this paper are a completely innovative formulation of the problem and involve application of Evolutionary Computing for this complex problem that may be extended to solutions of similar problems in VLSI design, distributed computing and many other applications.

Identifying network traffic features suitable for honeynet data analysis

A tunnel-based solution is presented in this paper to provide a resilient Internet access in face of a malicious act of denial of Internet access by higher-tier Internet service providers (ISPs). The proposed solution describes the different types of tunneling protocols that can be used, and the needed configurations to establish the tunnels. The validity of the proposed solution is demonstrated by means of network simulations using OPNET. Furthermore, the proposed solution is evaluated using different types of traffic generated by well known applications such as file transfer protocol (FTP) and video conferencing. We also considered different tunneling protocols such as IP-in-IP, generic routing encapsulation (GRE), and GRE with checksum under high traffic load. Based on the simulation results, the IP-in-IP tunneling protocol performs the best among all protocols considered in this work.

Software‐defined networking approach for enhanced evolved packet core network

The Internet is becoming a vital communication tool for individuals, businesses, and governments. Thus, the Internet access reliability is crucial especially against malicious behaviors. When a malicious higher-tier Internet service provider filters transit traffic for the purpose of dropping a specific networks packets, then an Internet access denial occurs. This paper presents a solution for the denial of the Internet access problem that combines a network address translation based solution with a tunnel-based solution. The network address translation based solution is efficient in terms of network performance but suffers from a server reachability problem; a problem that is solved by using a tunnel-based solution. Moreover, the paper evaluates the combined solution performance with respect to the end-to-end delay and the throughput metrics. The combined solution has insignificant effect on these two metrics when traffic originates from the denied network and is forwarded outside the denied network. In contrast, and dependent on the tunneling protocol used, the combined solution increases the end-to-end delay of the network by at least 6% and decreases the throughput of the traffic by at least 1.65% when the traffic is originated outside the denied network and is intended for servers inside the denied network. Copyright

Interdomain Traffic Engineering Techniques to Overcome Undesirable Connectivity Incidents

Recent advances in embedded computing systems have led to the emergence of wireless sensor networks (SNETs), consisting of small, battery-powered “motes” with limited computation and radio communication capabilities. SNETs permit data gathering and computation to be deeply embedded in the physical environment. Large-scale ad hoc sensor networks (ASNET) can provide dynamic data query architecture to allow the medical specialists to monitor patients remotely via (PDAs) or cellular phones. A three-layered architecture is proposed where sensors, microcontrollers, and central server/handhelds occupy the lower, middle, and top layers, respectively. The implemented network distinguishes between periodic sensor readings and critical where higher priority is given for the latter. In this paper we implement 3 special cases for tracking and monitoring patients and doctors using SNETs. Finally, the performance of a large scale of our implementation has been tested by means of simulations.