Monitoring and measuring various metrics of high data rate and high capacity networks produces a vast amount of information over a long period of time. Characteristics such as throughput and delay are derived from packet level information and can be represented as time series signals. This paper looks at the Embedded Zero Tree algorithm, proposed by Shapiro, in order to compress computer network delay and throughput measurements while preserving the quality of interesting features and controlling the level of quality of the compressed signal. The quality characteristics that are examined are the preservation of the mean square error (MSE), the standard deviation, the general visual quality (the PSNR) and the scaling behavior. Experimental results are obtained to evaluate the behaviour of the algorithm on delay and data rate signals. Finally, a comparison of compression performance is presented against the lossless tool bzip2.
{"title":"Compressing Computer Network Measurements Using Embedded Zerotree Wavelets","authors":"K. Kyriakopoulos, D. Parish","doi":"10.1109/AICT.2009.39","DOIUrl":"https://doi.org/10.1109/AICT.2009.39","url":null,"abstract":"Monitoring and measuring various metrics of high data rate and high capacity networks produces a vast amount of information over a long period of time. Characteristics such as throughput and delay are derived from packet level information and can be represented as time series signals. This paper looks at the Embedded Zero Tree algorithm, proposed by Shapiro, in order to compress computer network delay and throughput measurements while preserving the quality of interesting features and controlling the level of quality of the compressed signal. The quality characteristics that are examined are the preservation of the mean square error (MSE), the standard deviation, the general visual quality (the PSNR) and the scaling behavior. Experimental results are obtained to evaluate the behaviour of the algorithm on delay and data rate signals. Finally, a comparison of compression performance is presented against the lossless tool bzip2.","PeriodicalId":409336,"journal":{"name":"2009 Fifth Advanced International Conference on Telecommunications","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128749808","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Unlike other wireless technologies, the deployment of 802.11 networks is not limited to operators: access points can easily be installed by end-users for domestic use. This singular type of deployment is the reason why 802.11 networks are omnipresent in our urban landscapes. Indeed, in metropolitan areas, laptops frequently detect tens of 802.11 access points from the same location. In this work, we describe both simple and more complex data about access points obtained in two Paris districts during an extensive experiment from August to October 2007. We introduce a lightweight scanning platform that runs on common smartphones. Using the obtained data, we examine various parameters: (1) SSID, (2) manufacturers, (3) security modes, (4) density, (5) data rates, and (6) channels utilization. For example, we show that in the two districts that we mapped as few as 7% of the Wi-Fi networks are not secured. Similarly, we provide a practical evidence that 90% of detected access points where installed along with DSL Internet access.
{"title":"A Practical Characterization of 802.11 Access Points in Paris","authors":"Guillaume Valadon, F. L. Goff, Christophe Berger","doi":"10.1109/AICT.2009.44","DOIUrl":"https://doi.org/10.1109/AICT.2009.44","url":null,"abstract":"Unlike other wireless technologies, the deployment of 802.11 networks is not limited to operators: access points can easily be installed by end-users for domestic use. This singular type of deployment is the reason why 802.11 networks are omnipresent in our urban landscapes. Indeed, in metropolitan areas, laptops frequently detect tens of 802.11 access points from the same location. In this work, we describe both simple and more complex data about access points obtained in two Paris districts during an extensive experiment from August to October 2007. We introduce a lightweight scanning platform that runs on common smartphones. Using the obtained data, we examine various parameters: (1) SSID, (2) manufacturers, (3) security modes, (4) density, (5) data rates, and (6) channels utilization. For example, we show that in the two districts that we mapped as few as 7% of the Wi-Fi networks are not secured. Similarly, we provide a practical evidence that 90% of detected access points where installed along with DSL Internet access.","PeriodicalId":409336,"journal":{"name":"2009 Fifth Advanced International Conference on Telecommunications","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121998177","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The increasing demand for Voice over IP (VoIP) and the accompanying network convergence lead into a new area of security risks for voice infrastructures. A probability based risk analysis as an integral part of a security concept is presented which forges a hardened base system operating a voice platform. A modeling approach and a detailed system architecture is derived for the VoIP base system. Finally the security concept that was exemplarily implemented using freely available software packages (e.g. Linux, Asterisk) is described and results from verifications with several security test suites are highlighted.
IP语音(Voice over IP, Voice over IP)需求的增长以及随之而来的网络融合为语音基础设施带来了新的安全风险领域。提出了一种基于概率的风险分析方法，将其作为安全概念的组成部分，构建了一个运行语音平台的强化基础系统。推导了VoIP基础系统的建模方法和详细的系统体系结构。最后，本文描述了使用免费软件包(例如Linux、Asterisk)典型实现的安全性概念，并强调了使用几个安全性测试套件进行验证的结果。
{"title":"Probability Based Risk Analysis for a VoIP System","authors":"Michael Vahl, Stefan Boehmer, Thomas Oestreich","doi":"10.1109/AICT.2009.79","DOIUrl":"https://doi.org/10.1109/AICT.2009.79","url":null,"abstract":"The increasing demand for Voice over IP (VoIP) and the accompanying network convergence lead into a new area of security risks for voice infrastructures. A probability based risk analysis as an integral part of a security concept is presented which forges a hardened base system operating a voice platform. A modeling approach and a detailed system architecture is derived for the VoIP base system. Finally the security concept that was exemplarily implemented using freely available software packages (e.g. Linux, Asterisk) is described and results from verifications with several security test suites are highlighted.","PeriodicalId":409336,"journal":{"name":"2009 Fifth Advanced International Conference on Telecommunications","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114345142","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Consultative Committee for Space Data Systems (CCSDS) File Delivery Protocol (CFDP) is a new international standard developed by the space agency’s to meet the growing space communication need for effective transfer of information in a wide variety of mission configurations of inter-planetary space links. The performance of CFDP in the deferred NAK mode has been evaluated in a theoretical manner. The delivery latency mainly depended on timer used in both sender and receiver. In this paper we have proposed a dynamic NAK timer algorithm for CFDP in deferred NAK mode under bandwidth constrain. Then we have implemented and validated the algorithm in NS and also presented its performance results and analysis.
{"title":"Dynamic NAK Timer Algorithm to Improve Delivery Latency of CCSDS File Delivery Protocol in Deferred NAK Mode","authors":"M. Prathaban, J. Kohlenberg","doi":"10.1109/AICT.2009.59","DOIUrl":"https://doi.org/10.1109/AICT.2009.59","url":null,"abstract":"The Consultative Committee for Space Data Systems (CCSDS) File Delivery Protocol (CFDP) is a new international standard developed by the space agency’s to meet the growing space communication need for effective transfer of information in a wide variety of mission configurations of inter-planetary space links. The performance of CFDP in the deferred NAK mode has been evaluated in a theoretical manner. The delivery latency mainly depended on timer used in both sender and receiver. In this paper we have proposed a dynamic NAK timer algorithm for CFDP in deferred NAK mode under bandwidth constrain. Then we have implemented and validated the algorithm in NS and also presented its performance results and analysis.","PeriodicalId":409336,"journal":{"name":"2009 Fifth Advanced International Conference on Telecommunications","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125462013","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Hybrid Activation Multiple Access (HAMA) is a synchronous medium access protocol that maximizes the chance of link activations using code-division schemes. However, in HAMA there are two situations when a node's radio could rest (i.e., stay in sleep mode) without any other implications to the protocol itself. Nodes stay in idle when yielding (i.e., Yield state) to potential hidden terminals, or when there is no packet to be transmitted when they have a chance to do so. By switching the node's radio to a sleep state whenever possible, one can expect to not only save energy but also take advantage of the battery capacity recovery effect (due to the battery relaxation phenomena). However, when performing performance evaluation through simulations, one must adopt a more realistic battery model to account for the battery capacity recovery effect. In this work, we propose a new variant of HAMA, named Power Efficient Hybrid Activation Multiple Access (PHAMA), which takes advantage of wasted time slots for power saving and battery capacity recovery. To get an accurate estimate of the battery capacity gains, we adopt the Rakhmatov-Vrudhula battery model. Extensive simulation results show that PHAMA provides simple ways to extend the network lifetime compared to the original HAMA protocol.
{"title":"Power Efficient Hybrid Channel Access Scheduling in Wireless Multihop Networks","authors":"M. Spohn","doi":"10.1109/AICT.2009.54","DOIUrl":"https://doi.org/10.1109/AICT.2009.54","url":null,"abstract":"Hybrid Activation Multiple Access (HAMA) is a synchronous medium access protocol that maximizes the chance of link activations using code-division schemes. However, in HAMA there are two situations when a node's radio could rest (i.e., stay in sleep mode) without any other implications to the protocol itself. Nodes stay in idle when yielding (i.e., Yield state) to potential hidden terminals, or when there is no packet to be transmitted when they have a chance to do so. By switching the node's radio to a sleep state whenever possible, one can expect to not only save energy but also take advantage of the battery capacity recovery effect (due to the battery relaxation phenomena). However, when performing performance evaluation through simulations, one must adopt a more realistic battery model to account for the battery capacity recovery effect. In this work, we propose a new variant of HAMA, named Power Efficient Hybrid Activation Multiple Access (PHAMA), which takes advantage of wasted time slots for power saving and battery capacity recovery. To get an accurate estimate of the battery capacity gains, we adopt the Rakhmatov-Vrudhula battery model. Extensive simulation results show that PHAMA provides simple ways to extend the network lifetime compared to the original HAMA protocol.","PeriodicalId":409336,"journal":{"name":"2009 Fifth Advanced International Conference on Telecommunications","volume":"45 4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131549113","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
With the technological changes on the horizon, there seems significant potential for availability of telecommunications access, and hence services. Many incumbent telecommunications operators are announcing a transition to socalled Next Generation Networks (NGN) to replace their existing networks. Such changes are expected to have significant implications in the way services are provided and the characteristics of these services. Step towards NGN leads to heterogeneity and complexity. NGN is based on distributed architecture that involves multiple equipments and applications to offer innovative services. Hence traditional service management will not be able to support NGN services. This paper discusses the ideas about the advanced management services for NGN. Network intelligence will not just relate to the creative routing of connection based on simple database look-ups, but may take on much broader meaning.
{"title":"Next Generation Approach towards Management","authors":"B. Ambudkar","doi":"10.1109/AICT.2009.87","DOIUrl":"https://doi.org/10.1109/AICT.2009.87","url":null,"abstract":"With the technological changes on the horizon, there seems significant potential for availability of telecommunications access, and hence services. Many incumbent telecommunications operators are announcing a transition to socalled Next Generation Networks (NGN) to replace their existing networks. Such changes are expected to have significant implications in the way services are provided and the characteristics of these services. Step towards NGN leads to heterogeneity and complexity. NGN is based on distributed architecture that involves multiple equipments and applications to offer innovative services. Hence traditional service management will not be able to support NGN services. This paper discusses the ideas about the advanced management services for NGN. Network intelligence will not just relate to the creative routing of connection based on simple database look-ups, but may take on much broader meaning.","PeriodicalId":409336,"journal":{"name":"2009 Fifth Advanced International Conference on Telecommunications","volume":"277 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134251503","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Optical Code Division Multiple Access (OCDMA) systems, intensively investigated these last years, are known to suffer from Multiple Access Interference (MAI). In addition, the photodetection process leads to beatings between the desired user information and the interferer ones, strongly degrading the system performance. To simplify the performance analysis, noise statistic is generally approximated by a Gaussian distribution which is not very accurate regarding to optical considerations. In this paper, by considering beat noise along with MAI, we develop a more precise analysis of the probability density function of the decision variable as a mixture of chi-square distributions. To investigate beat noise impact, the theoretical error probability expression is then determined. The results permit obtaining the conditions required to reach the optimal performance in beat noise corrupted OCDMA systems.
{"title":"OCDMA Channel Statistic as a Mixture of Chi-Square Distributions","authors":"S. Sahuguède, A. Julien-Vergonjanne, J. Cances","doi":"10.1109/AICT.2009.49","DOIUrl":"https://doi.org/10.1109/AICT.2009.49","url":null,"abstract":"Optical Code Division Multiple Access (OCDMA) systems, intensively investigated these last years, are known to suffer from Multiple Access Interference (MAI). In addition, the photodetection process leads to beatings between the desired user information and the interferer ones, strongly degrading the system performance. To simplify the performance analysis, noise statistic is generally approximated by a Gaussian distribution which is not very accurate regarding to optical considerations. In this paper, by considering beat noise along with MAI, we develop a more precise analysis of the probability density function of the decision variable as a mixture of chi-square distributions. To investigate beat noise impact, the theoretical error probability expression is then determined. The results permit obtaining the conditions required to reach the optimal performance in beat noise corrupted OCDMA systems.","PeriodicalId":409336,"journal":{"name":"2009 Fifth Advanced International Conference on Telecommunications","volume":"328 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134315698","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this paper we present and analyze an algorithm aimed at link management for mobile ad-hoc networks. There are frequent link failures in an ad-hoc network especially if there is high mobility of nodes. Routing protocols thus have to ensure that the path used for communication is not outdated. For this, different approaches have been proposed. Our proposed mechanism improves the techniques which are used nowadays and is based on signal strength measurements. It takes into account temporal as well as signal strength stability of a link. This information helps in anticipating link breakages and guarantees that only those links that have good quality are used for communication. This makes the link management more robust thereby greatly improving the performance.
{"title":"Analytical Evaluation and Dimensioning of a Cross-Layer Link Sensing Algorithm","authors":"Husnain Mansoor Ali, A. Busson, V. Vèque","doi":"10.1109/AICT.2009.11","DOIUrl":"https://doi.org/10.1109/AICT.2009.11","url":null,"abstract":"In this paper we present and analyze an algorithm aimed at link management for mobile ad-hoc networks. There are frequent link failures in an ad-hoc network especially if there is high mobility of nodes. Routing protocols thus have to ensure that the path used for communication is not outdated. For this, different approaches have been proposed. Our proposed mechanism improves the techniques which are used nowadays and is based on signal strength measurements. It takes into account temporal as well as signal strength stability of a link. This information helps in anticipating link breakages and guarantees that only those links that have good quality are used for communication. This makes the link management more robust thereby greatly improving the performance.","PeriodicalId":409336,"journal":{"name":"2009 Fifth Advanced International Conference on Telecommunications","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131469847","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Optical Packet Switched (OPS) ring Metropolitan Area Networks (MAN) are among the most promising solutions for Next Generation MAN architectures. However, a particular phenomenon is observed in optical ring networks with random access to the transmission medium, such as in asynchronous Optical Unslotted Carrier Sense Multiple Access with Collision Avoidance (OU-CSMA/CA). Due to the random moments of packet transmissions, the amount of bandwidth which is available for use, on each wavelength, becomes divided into many small pieces. This problem, also called bandwidth fragmentation, causes a waste of some transmission resources. In fact, free spaces which are smaller then the optical packet size are out of use for traffic insertion. The bandwidth fragmentation is reduced in synchronous networks, thanks to the better use of the transmission resources provided by these networks [6]. This paper describes an access scheme that is proposed to improve the performance of the original OU-CSMA/CA applied to an asynchronous optical ring network. We propose a “virtual synchronization” mechanism (VSC), which improves significantly the bandwidth utilization while being very simple to implement. We provide simulation works in order to validate the efficiency of the proposed mechanism. Numerical results show the improvement of performance provided by the VSC mechanism, compared to the original CSMA/CA protocol.
{"title":"Performance of a Virtual Synchronization Mechanism in an Asynchronous Optical Network","authors":"D. Nguyen, T. Eido, T. Atmaca","doi":"10.1109/AICT.2009.13","DOIUrl":"https://doi.org/10.1109/AICT.2009.13","url":null,"abstract":"Optical Packet Switched (OPS) ring Metropolitan Area Networks (MAN) are among the most promising solutions for Next Generation MAN architectures. However, a particular phenomenon is observed in optical ring networks with random access to the transmission medium, such as in asynchronous Optical Unslotted Carrier Sense Multiple Access with Collision Avoidance (OU-CSMA/CA). Due to the random moments of packet transmissions, the amount of bandwidth which is available for use, on each wavelength, becomes divided into many small pieces. This problem, also called bandwidth fragmentation, causes a waste of some transmission resources. In fact, free spaces which are smaller then the optical packet size are out of use for traffic insertion. The bandwidth fragmentation is reduced in synchronous networks, thanks to the better use of the transmission resources provided by these networks [6]. This paper describes an access scheme that is proposed to improve the performance of the original OU-CSMA/CA applied to an asynchronous optical ring network. We propose a “virtual synchronization” mechanism (VSC), which improves significantly the bandwidth utilization while being very simple to implement. We provide simulation works in order to validate the efficiency of the proposed mechanism. Numerical results show the improvement of performance provided by the VSC mechanism, compared to the original CSMA/CA protocol.","PeriodicalId":409336,"journal":{"name":"2009 Fifth Advanced International Conference on Telecommunications","volume":"47 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131860379","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Petros Nicopolitidis, G. Papadimitriou, A. Pomportsis, K. Pappas
This paper proposes a Low Power Adaptive (LPA) MAC protocol for ad-hoc Wireless LANs (WLANs), which is capable of operating efficiently under bursty traffic conditions. The protocol utilizes a Learning Automaton at each node of the WLAN. Each Automaton utilizes network feedback to select the mobile station that will be granted permission to transmit. We implement a low-power option to reduce the energy consumption of the protocol in medium-to high network loads.
{"title":"A Mac Protocol for Ad-Hoc Wireless Lans with Reduced Energy Consumption","authors":"Petros Nicopolitidis, G. Papadimitriou, A. Pomportsis, K. Pappas","doi":"10.1109/AICT.2009.67","DOIUrl":"https://doi.org/10.1109/AICT.2009.67","url":null,"abstract":"This paper proposes a Low Power Adaptive (LPA) MAC protocol for ad-hoc Wireless LANs (WLANs), which is capable of operating efficiently under bursty traffic conditions. The protocol utilizes a Learning Automaton at each node of the WLAN. Each Automaton utilizes network feedback to select the mobile station that will be granted permission to transmit. We implement a low-power option to reduce the energy consumption of the protocol in medium-to high network loads.","PeriodicalId":409336,"journal":{"name":"2009 Fifth Advanced International Conference on Telecommunications","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123601280","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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