1,721,135 research outputs found
Bandwidth management in live virtual machine migration
Full text linkIn this thesis I investigated the bandwidth management problem on live migration of virtual machine in different environment. First part of the thesis is dedicated to intra-data-center bandwidth optimization problem, while in the second part of the document I present the solution for wireless live migration in 5G and edge computing emerging technologies.
Live virtual machine migration aims at enabling the dynamic balanced use of the networking/computing physical resources of virtualized data centers, so to lead to reduced energy consumption and improve data centers’ flexibility. However, the bandwidth consumption and latency of current state-of-the-art live VM migration techniques still reduce the experienced benefits to much less than their potential. Motivated by this consideration I analytically characterize and test the optimal bandwidth manager for intra-data-center live migration of VMs. The goal is to min- imize the migration-induced communication energy consumption under service level agreement (SLA)-induced hard constraints on the total migration time, downtime, slowdown of the migrating applications and overall available bandwidth
Security analiysis of IEEE 802.16
No full textThis paper analyzes some critical security issues in the family of IEEE 802.16 standard that has not been addressed so far. In particular two of the key features of the standard, the dynamic resources allocation and the mesh mode revealed to be vulnerable to attacks that represent serious threats to the robustness and privacy of the communications. In the first case the attacker is able to reduce bandwidth assigned to its neighbors, with the aim of obtaining more resources for himself;
in the second case, we observed that there might be no real privacy in communications between two nodes of the mesh network. These vulnerabilities are still present even after the latest amendment to the standard, IEEE 802.16e that solved some previously addressed security flaws
S.T.R.E.S.S. : Stress Testing and Reverse Engineering for System Security
Full text linkIn modern wireless networks the functions included into layer
II have to deal with complex problems, such as security and
access control, that were previously demanded to upper layers.
This growing complexity led some vendors to implement layer
II primitives directly in software, e.g. IEEE 802.11i has been
largely distributed as a software patch to be used with legacy
802.11b/g hardware. In any extremely complex software the
likelihood of committing errors during the implementation raises,
and it is well known that software bugs can lead to instability
of the system and possibly to security vulnerability. Software
bugs are the most common cause of successful attacks against
any kind of network and represent a real plague for system
administrators. Stress test is a widely used methodology to
find and eliminate software bugs. In this paper we present a
platform to perform a stress test of generic network protocols
implementations but especially optimized for Layer II stress tests,
that present specific problems. With our approach a generic
network protocol described with ABNF language can be tested
transmitting arbitrary frame sequences and interpreting the
responses to verify consistence with the communication standard
used. Our platform can interact dynamically with the tested
machine (an access point, a router etc.) to verify its robustness
and its compliance with the standard. Experiments confirmed the
validity of our approach both as a stress test technique for system
under development and as a reverse engineering technique for
interaction with closed source system
An M2M cognitive MAC protocol for overlaid OFDMA environments
No full textMachine to machine (M2M) communications have gained in the last years an increasing interest due to ever growing number of machine-type devices that are used in different application fields by allowing low cost and efficient communications among devices mainly in an autonomous manner. Even if M2M protocols need of dedicated resources, a new paradigm called cognitive M2M (CM2M) has been recently introduced in order to exploit cognitive/opportunistic radio communications. The aim of this paper is to outline a CM2M mechanism, where the primary network is based on the orthogonal frequency division multiple access technique, while the M2M communication-based secondary network uses a novel medium access control technique, named data aided cognitive technique (DACT). The performance of the proposed DACT protocol is derived by means of suitable analytical methods under different operational conditions. Analytical predictions are also validated by comparisons with numerical results obtained through computer simulations, in order to show the effectiveness of the proposed solution in terms of throughput, delay, resource wastage and CM2M devices queue length; to this aim, the proposed DACT protocol has been implemented with different alternatives. Among them, an adaptive approach allows to optimise the system performance by increasing the overall throughput while keeping under control the system delay and the resource wastage
Mesh network firewalling with Bloom Filters
No full textThe nodes of a multi-hop wireless mesh network often share a single physical media for terminal traffic and for the backhaul network, so that the available resources are extremely scarce. Under these conditions it is important to avoid that unwanted traffic may traverse the network subtracting resources to authorized terminals. Packet filtering in wireless mesh networks is an extremely challenging task, since the number of possible connections is quadratic with respect to the number of the terminals of the network; for each connection a rule is needed and the time needed for filtering grows linearly with the number of rules. Moreover nodes can be in possession of end users and the administrator might want to keep the explicit ruleset as much secret as possible while giving the nodes enough
data to behave as a firewall. In this article we present a solution for distributed firewalling in multi-hop mesh networks based on the use of Bloom Filters, a powerful but compact data structure allowing probabilistic membership queries
Efficient packet filtering in wireless ad-hoc networks
No full textWireless ad hoc networks are an emerging technology. These networks are composed of mobile nodes and may adopt different topologies depending on the nature of the environment. Nevertheless, they are vulnerable to network layer attacks that cannot be neutralized easily. In wired networks, firewalls improve the level of
security by means of packet filtering techniques that determine what traffic is allowed, thereby reducing the impact of such attacks. In this work, we overview the requirements to adapt firewalls to wireless ad hoc networks and highlight the advantages of the use of filtering techniques based on Bloom filters
Proposal of a Cognitive Based MAC Protocol for M2M Environments
No full textThe radio resource shortage is one of the most important issues to be taken into account when deploying modern wireless communication systems. A novel communication paradigm named cognitive radio, has been introduced in the last years for a more efficient exploitation of the limited available spectrum and cope with the inefficiency in the spectrum usage. Its main aim is to allow the co-existence of different wireless systems on the same spectral resources by limiting the mutual interference. The aim of this paper is to design a cognitive
networking environment where the primary network is based on the OFDMA principle. The proposed Medium Access Control (MAC) technique for the secondary network, named Data Aided Cognitive Technique (DACT), aims to exploit the framing information broadcast by the primary network in order to setup transparently an independent network with a particular focus on Machine to Machine (M2M) communications
Cognitive Radio Techniques for M2M Environments
No full textMachine to Machine (M2M) communications have been recently introduced as a viable paradigm for allowing low cost and efficient communications among devices mainly in an autonomous manner. Even if M2M protocols need dedicated resources, a new paradigm, called Cognitive M2M (CM2M) communications, has been recently considered exploiting cognitive/opportunistic radio communications. After having introduced the problem of applying cognitive techniques in M2M scenarios, the authors focus their attention on the Medium Access Control (MAC) protocols for CM2M scenarios, with a particular attention on the OFDMA-based primary systems. Among other approaches, the authors focus on a data-aided approach for the access of the secondary devices aiming to reduce interference toward the primary system
Lightweight, distributed access control for wireless sensor networks supporting mobility
No full textWireless sensor networks (WSN) are large scale networks of unattended devices, aimed at monitoring environmental parameters. Their extremely scarce hardware resources constitute a huge limitation to the use of standard security protocols to secure communications, so that custom ones must be designed. In this article we describe the development of a novel access control system for WSN based on a distributed threshold scheme. Our model gives support for mobility and limits the
needed communication and consequent energy drain, which is a fundamental parameter for the lifetime of WSN
Green multimedia wireless sensor networks: Distributed intelligent data fusion, in-network processing, and optimized resource management
No full textIn developing new applications for green wireless media, power-efficient paradigms and distributed platforms for pervasive sensing, efficient fusion, QoE dissemination, and real-time recovery of multimedia data are of paramount importance. In particular, these topics are challenging in MWSN applications to be compliant with the green wireless media paradigm. In this article, we review the current state of the art in green QoE MWSNs, with reference to mobile users and remote applications. At first, the most relevant aspects regarding the fusion, storage, transmission, and retrieval of multimedia data are reviewed and critically discussed. Afterward, we present some recent paradigms and trends in power-efficient QoE multimedia data fusion and clustering, and collaborative context-aware realtime in-network processing that may serve as guidelines for future green media applications. © 2002-2012 IEEE
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