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Záviš, Jan. "Model křižovatky s průmyslovou komunikací." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2021. http://www.nusl.cz/ntk/nusl-442438.
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This diploma project summarizes a theoretical introduction regarding the issue of traffic light control. Further there is industrial communication discussed, where they are the Ethernet / IP protocol and the Modbus TCP protocol described more in detail. The following is the description of the Logix series programmable controllers. Then the diploma follows up with market research in order to find the most suitable development kit which is used as a trial prototype. Then it is concerned with a development kit with a communication module from AND-TECH company. Software was developed on them, more specifically a library for processor ports, memory and the Modbus TCP protocol. After verifying the functionality of the software, the hardware design was started. From the first site it is development kit and module and from the second site there are input and output circuits. There must be the assessment of the results found during the test operation. The end of the document describes incorrect steps that were repaired in hardware.
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Otčenášek, Martin. "Distribuované řídící systémy a jejich využití v praxi." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2008. http://www.nusl.cz/ntk/nusl-217601.
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In control technique there is evident highly expressive trend of shifting from efficient central managing systems towards smaller systems which are distributed on technology and which are connected by communication bus. There is no need to link all signals to central management system, operation is then distributed and realized directly in individual parts of technology. That’s why these systems are called distributive managing systems. Distributive managing systems are widely used not only in industrial applications but also in buildings, cars, etc..
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Ramalata, Mulalo Phillip. "Development and implementation of a modbus based wireless air protocol." Thesis, Stellenbosch : Stellenbosch University, 2004. http://hdl.handle.net/10019.1/49910.
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Thesis (MScEng)--University of Stellenbosch, 2004.<br>ENGLISH ABSTRACT: The recent performance improvements of wireless communication systems are presenting
possibilites for the use of wireless networks for industrial applications, which typically
impose severe restrictions in terms of response time and flexibility.
Traditionally most of the industrial protocols employ cable connections, which have limitations
in terms of flexibility and development oportunities. The industrial protocol used
for this project, is the Modbus protocol. This protocol is developed and implemented on a
wireless environment by using data radio modems. The Modbus protocol is a master/slave
protocol which provides an industry standard for industrial data transfer.
A Modbus driver is designed for radio networks, so that it can function with different
PLCs and SCADA packages, supporting Modbus protocol. This enables control and
monitoring to be excercised over a long distance, and enables control equipment to be
placed as required and not with particular wiring restrictions.<br>AFRIKAANSE OPSOMMING: Die onlangse verbetering in radiokommunikasiestelsels bied moontlikhede vir die gebruik
van radionetwerke vir industriële toepassings, wat gewoonlik streng beperkings plaas in
terme van responstyd en buigbaarheid. Tradisioneel is meeste van die industriële protokolle
kabelgebaseer, wat redelik onaanpasbaar is.
Die Modbus protokol is as basis in hierdie projek gebruik. Dit is 'n meester/slaaf industriestandaard,
wat hier aangepas is vir toepassings met radiomodems. Die Modbus drywer
is ontwerp om funksioneel te wees met 'n verskeidenheid van PLC's en SCADA pakette,
wat die Modbus protokolondersteun. Dit stel beheer- en meetaksies in staat oor lang
afstande en laat relatief vrye plasing toe van toerusting sonder bedradingsbeperkings.
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Šoustar, Jiří. "Modul rozhraní Ethernet pro platformu FITkit." Master's thesis, Vysoké učení technické v Brně. Fakulta informačních technologií, 2008. http://www.nusl.cz/ntk/nusl-235428.
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This graduation thesis is aimed at design and implementation of embedded systems, network communication and support of the network communication for embedded systems. Furthermore it introduces school platform FITkit and offers a conceptional extension of the network interface for this platform based on Ethernet network standard. Based on that conception I'm trying to find and describe suitable solution for FITkit platform which realizes a network interface as a form of extension module capable of development supporting.
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Lai, Chengdi, and 赖成迪. "Congestion control for transmission control protocol (TCP) in wirelessnetworks." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2011. http://hub.hku.hk/bib/B47102445.
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The best MPhil thesis in the Faculties of Dentistry, Engineering, Medicine and Science (University of Hong Kong), Li Ka Shing Prize,2010-11.<br>published_or_final_version<br>Electrical and Electronic Engineering<br>Master<br>Master of Philosophy
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Mouton, A. J. J., C. J. Smith, and G. E. Smith. "An efficient communication interface and protocol for motor protection relays." Journal for New Generation Sciences, Vol 7, Issue 1: Central University of Technology, Free State, Bloemfontein, 2009. http://hdl.handle.net/11462/524.
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Published Article<br>A company in South Africa is a three-phase induction motor protection relay manufacturer. The function of the protection relay is to capture running data, to provide protection against possible damage, to control an electric motor and to communicate this data to the System Control and Data Acquisition (SCADA) system in a control room. In the case of remote sites e.g. a pump station, the protection relays are used as standalone units. The protection relays are equipped with communication facilities to be used in an instrumentation environment. If a trip occurs or settings need to be changed a technician has to visit the remote site and address the problem. The ideal cost and time effective solution is to perform these tasks remotely via a reliable wireless network.
A study was conducted to ascertain the viability of using the standard GSM cellular networks in South Africa to effectively control electric motors and to communicate with the Motor Protection Relays (MPRs) controlling the electric motors in order to determine the status of a motor, settings of the motor, trips that occurred and time of occurrence. It was shown that a node controller could be used to store all the data from various electric motors at a single location. It was also shown that the data from the different electric motors could be analysed at the node controller and that communication can then be initiated from the controller to a responsible person via the GSM network. It was further illustrated that, by making use of the GSM networks in South Africa together with the short message service (SMS), communication and control can be effectively established. SMSs proved to be a reliable means of communication between cellular phones, an embedded network and MPRs. It was shown that software protocols, although slower in communication speed, proved to be reliable and effective for the purpose of transferring information between the node controller and the motor protection relays connected to the electric motors.
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Gupta, Pawan Kumar. "Throughput Enhancement of TCP over Wireless Links." Thesis, Indian Institute of Science, 2002. http://hdl.handle.net/2005/48.
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The congestion control mechanisms of Transmission Control Protocol (TCP) are very effective in providing best effort service in wired networks, where packet losses are mainly due to congestion in the network. In wireless mobile networks, more often than not, loss of packets is because of corruption of data on the wireless link. The TCP sender responds to these losses as if they are due to congestion, by reducing its congestion window, thereby reducing the rate of flow of packets. The reduction in congestion window is a necessity when network is experiencing congestion to avoid congestion collapse but it is not required if packet losses occur due to corruption of data on the wireless link. This unnecessary reduction in congestion window for corruption losses is the main reason for poor throughput of data transfer in wireless networks. The reduction in congestion window for corruption losses can be avoided if TCP can successfully differentiate between packet losses due to congestion and corruption.
We suggest enhancements to TCP that, if implemented, will help the TCP receiver in separately identifying corruption losses and congestion losses. The enhancements are suggested over and above standard TCP NewReno and we call this new scheme as "NewRenoEln (NewReno with Explicit Loss Notification)". We suggest that the TCP sender attach a separate checksum for the TCP header with the packet. Since the length of the TCP header is much smaller as compared to the length of the TCP packet, there is a large probability that the TCP receiver will receive the header portion of the TCP packet without error even if the data portion of the packet is corrupted. Once the header information is found to be correct for a corrupted packet, the receiver can generate reliable Explicit 5oss Notification (ELN) for the sender.
We derive an expression for the probability of a receiver generating successful Explicit
Loss Notification, assuming a generic link layer protocol that is used for data transfer over wireless link. With this analysis, we show that there is large probability that receiver will generate successful ELN for various channel conditions We also suggest modifications to the sender behavior on receiving successful Explicit Loss Notification from the receiver. With these modifications, the TCP sender will recover from corruption losses without any reduction in congestion window.
There is also a need to develop a unified analytical approach for the evaluation of
TCP performance. We develop an analytical approach for the performance evaluation of
NewRenoEln scheme. We compare the throughput results obtained by analytical calculations with results obtained by simulation and find them to be very close to each other.
We also compare the performance of the proposed scheme NewRenoEln and the standard NewReno TCP via simulation as well as analytical approach, and find considerable improvement in throughput over wireless links.
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Yuen, Kwan Hung. "TCP performance over satellite networks /." View Abstract or Full-Text, 2003. http://library.ust.hk/cgi/db/thesis.pl?COMP%202003%20YUEN.
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Thesis (M. Phil.)--Hong Kong University of Science and Technology, 2003.<br>Includes bibliographical references (leaves 68-71). Also available in electronic version. Access restricted to campus users.
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Li, Zhi. "TCP adaptation schemes in heterogeneous and ad hoc wireless networks." Click to view the E-thesis via HKUTO, 2005. http://sunzi.lib.hku.hk/hkuto/record/B32037326.
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Li, Zhi, and 李志. "TCP adaptation schemes in heterogeneous and ad hoc wireless networks." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2005. http://hub.hku.hk/bib/B32037326.
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Pyk, Axel. "Multipath TCP : Performance in a LTE Environment." Thesis, Linköpings universitet, Databas och informationsteknik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-129123.
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The market penetration of mobile access devices with multiple network interfaces has increased dramatically over the last few years. As a consequence, the quest for a widespread multi-path transport protocol that takes advantage of all available interfaces simultaneously to increase data throughput and improve robustness, has received considerable attention. One prominent protocol introduced by the IETF is Multipath TCP (MPTCP). MPTCP is an extension to the predominant single-path transport protocol, the Transport Control Protocol (TCP) that enables multihomed devices to aggregate available resources transparently to the applications. Combining multiple radio access technologies, like LTE and Wi-Fi, with diverse characteristics in terms of transmission rates and fluctuations opens for novel challenges that may disrupt and even harm the data throughput. Therefore MPTCP must take path heterogeneity into account. For MPTCP to supersede single-path TCP it is required that MPTCP always achieve at least the throughput of the best individual TCP path. This thesis investigates if MPTCP with uncoupled congestion control fulfills this condition, and if so, how much it improves the throughput. By examining the protocol in a deterministic emulated environment defined by the characteristics of LTE, we conclude two key factors impacting the outcome: the download size and the difference in characteristics between the paths. Our experiments show that MPTCP overall fulfills this task, especially during path homogeneity with near aggregated results. But we also show that MPTCP may decrease data throughput with 16% compared to TCP during path heterogeneity. Hence MPTCP does not always fulfill the goal of throughput. We therefore conclude further intelligence is needed for the packet scheduling mechanism to avoid throughput degradation in the initial phase of a transmission.
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Jayananthan, Aiyathurai. "TCP performance enhancement over wireless networks." Thesis, University of Canterbury. Electrical and Computer Engineering, 2007. http://hdl.handle.net/10092/1229.
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Transmission Control Protocol (TCP) is the dominant transport protocol in the Internet and supports many of the most popular Internet applications, such as the World Wide Web (WWW), file transfer and e-mail. TCP congestion control algorithms dynamically learn the network bandwidth and delay characteristics of a network and adapt its performance to changes in traffic so as to avoid network collapse. TCP is designed to perform well in traditional wireline networks with the assumptions that packet losses are mainly due to network congestion and random bit error rate (BER) is negligible. However, networks with wireless links suffer from significant packet losses due to random bit errors and handoffs. Hence TCP performs poorly in networks with wireless links because it treats any packet loss in the network to be a result of network congestion and slows down its transmission rate, or even cause the TCP sender to experience unnecessary timeouts, further reducing its performance. The development of advance wireless networks, such as WiFi, UMTS and WiMAX, make it necessary to find ways to improve TCP's efficiency and resource utilization, as well as improve the user's experience and reduce latency times. In order to find effective solutions to this effect, packet losses across wireless links should be distinguished from congestion related packet losses. In this thesis, we concentrate on two main strategies for enabling the TCP congestion control mechanism to determine the cause for a packet loss. One is a proxy-based mechanism that monitors the radio network interface and sends radio network feedback (RNF) to the TCP sender with the status of the wireless link. The other one is an end-to-end mechanism, in which the packet error pattern is used as the system metric to fine-tune the congestion control mechanism. It also presents an analytical model of TCP with enhanced recovery mechanism for wireless environments. In a proxy-based mechanism, TCP sender is explicitly informed of any effects caused by wireless links. However, the implementation technique is network dependent. We have proposed and developed three proxy-based schemes; the radio network feedback (RNF) scheme over an 802.11 WLAN network, the radio network controller (RNC) feedback over a UMTS network and a wireless enhancement proxy (WENP) over both the 802.11 WLAN and UMTS networks. The RNF scheme is introduced at the 802.11 WLAN base station that monitors the TCP packet flows over the wireless links, detects wireless packet losses and provides feedback to the TCP sender using one of the TCP header reserved control bits, called RNF flag. TCP Reno is modified to utilize the radio network feedback to distinguish the losses due to wireless effects form the congestion and fine-tuned to perform wireless enhanced fast retransmit and fast recovery mechanisms. The RNF scheme is implemented using the OPNET tool, and the simulation results show that the TCP performance is significantly improved. The RNC feedback mechanism, similar to the RNF scheme, is developed and implemented in a UMTS network. The GPRS Tunneling Protocol (GTP) layer of the UMTS Radio Network Control (RNC) protocol stack was modified to detect and notify the TCP sender of the wireless packet losses, which is the main difference between the RNF and RNC mechanisms. The simulation results shows that the RNC feedback mechanism significantly improves the TCP performance compared to that of standard TCP over UMTS. The wireless enhancement proxy (WENP) is developed to minimize spurious TCP timeouts over wireless networks and implemented in both 802.11 WLAN and UMTS networks. WENP extends the proposed RNF and RNC feedback mechanisms to detect both wireless packet losses and large delays across the wireless link, and to notify the TCP sender of these events with the aid of two reserved bits in the TCP header. TCP Reno is further modified to utilize the WENP feedback to distinguish both wireless packet losses from congestion losses and spurious timeouts from normal timeouts. It is also fine-tuned to perform both the wireless enhanced fast retransmit and fast recovery mechanism and the timeout mechanism. The simulation results demonstrate that the proposed scheme markedly improves the TCP performance compared to that of standard WLAN and UMTS implementations. An end-to-end early packet loss recovery (EPLR) mechanism that modifies the TCP Reno fast retransmit algorithm to detect packet losses early and to speed up the packet recovery process to reduce the number of TCP timeouts over networks with heavy packet losses, such as wireless networks is also presented. TCP Reno with EPLR scheme is implemented in a UMTS network and its performance is compared with that of TCP Reno and New Reno. Simulation results shows that Reno with EPLR improves the TCP performance and application response time significantly compared to that of both Reno and New Reno by reducing the TCP timeouts, which is the main cause of degradation of the TCP performance in a wireless environment. Finally, we develop an analytical TCP throughput model with enhanced TCP Reno fast retransmit algorithm to avoid timeouts. The model captures the TCP fast retransmit mechanism and expresses the steady state congestion window and throughput as a function of network utilization factor, round trip time (RTT) and loss rate. Another new feature added to the model is dynamic adjustment of the congestion window size depending on the packet drop rates. This speeds up the packet recovery process and reduces the number of TCP timeouts over networks with heavy packet losses. The proposed model is implemented over a UMTS network and its performance is compared with that of TCP Reno. Simulation results show that the proposed model reduces the TCP timeouts and improves the TCP performance compared to that of TCP Reno. It is also found that the model provides a very good match to the steady-state congestion window behavior.
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Klimov, Illia, and Oryna Podoba. "Improvement of the Architecture and Communication Protocol of a Sensor-based IT System." Thesis, Linnéuniversitetet, Institutionen för datavetenskap (DV), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-31121.
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Communication protocols based on SMS and e-email are simple and straightforward to implement yet they possess a significant communication overhead and delay. In a large sensor network this would increasingly lead to performance issues and decrease scalability of the overall system, since SMS and e-mail include a significant transmission delay and overhead. Additionally, a communication architecture, where clients communicate directly to the central server requires these to be online all the time, thus decreasing battery time. We replaced the initial SMS and e-mail based communication protocol with a TCP based protocol. Furthermore, we selected a new architecture where sensor groups could communicate to a master node in that group, which in turn communicates to the central server. These changes were implemented in an emulator, since the real sensors could not be reconfigured. We evaluated the improvements and could show that we can reduce the communication overhead and transmission delay as well as that the average battery time for all sensors in a group is increased.<br>Emulator for complex sensor-based IT system
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Chen, Qizhong. "Identifying and analyzing sources of overhead in the TCP/IP communication protocol over a local area network." Thesis, This resource online, 1991. http://scholar.lib.vt.edu/theses/available/etd-12052009-020017/.
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Protopopov, Boris Vladimirovich. "Effects of communication protocol stack offload on parallel performance in clusters." Diss., Mississippi State : Mississippi State University, 2003. http://sun.library.msstate.edu/ETD-db/theses/available/etd-06272003-120226/unrestricted/etd%5Fbprotopopov%5F070903.pdf.
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Scofield, Dan. "Hop-by-hop transport control for multi-hop wireless networks /." Diss., CLICK HERE for online access, 2007. http://contentdm.lib.byu.edu/ETD/image/etd1812.pdf.
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Anantharaman, Vaidyanathan. "Reliable transport over multihop wireless Ad Hoc Networks." Thesis, Georgia Institute of Technology, 2002. http://hdl.handle.net/1853/15427.
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Alazemi, Hamed M. K. "Modeling and analysis of stochastic self-similar processes and TCP/IP congestion control in high-speed computer communication networks /." Thesis, Connect to this title online; UW restricted, 2000. http://hdl.handle.net/1773/6000.
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Tian, Jun. "A speed adaptive mobile Internet protocol over wireless local area network." [Gainesville, Fla.] : University of Florida, 2005. http://purl.fcla.edu/fcla/etd/UFE0012700.
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Rahme, Sandy. "Détection et estimation d'anomalies dans un réseau de communication." Phd thesis, Université Paul Sabatier - Toulouse III, 2011. http://tel.archives-ouvertes.fr/tel-00667420.
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La supervision des réseaux de communication et plus particulièrement la détection d'anomalies représente un aspect important de la Qualité de Service. Les anomalies sont des circonstances où certaines opérations dévient de leur comportement normal. Certaines sont causées par des problèmes physiques ou techniques comme la panne d'électricité ou les échecs de serveur de fichier, des changements brusques causés par le trafic légitime comme la surcharge du réseau, les foules subites, ainsi que des comportements risqués illégitimes comme des attaques de Déni de Service (DdS) et Déni de Service Distribué (DddS). Nous confrontons la problématique de détection et reconstruction des anomalies parvenant au modèle TCP/IP par la théorie de commande. Ces anomalies sont considérées comme des défauts dans un modèle mathématique représentant la dynamique du modèle TCP/IP. Dans le domaine de détection des défauts, les observateurs peuvent être classés, selon la connaissance du profil des défauts, en observateurs à entrée connue ou à entrée inconnue. Notre première contribution en termes de synthèse d'observateurs à entrées connues se limite à des formes polynômiales pouvant recouvrir une large gamme d'anomalies. L'anomalie et ses dérivées successives introduites dans l'espace d'état du système sont reconstruites par des observateurs de Luenberger. La construction des observateurs étant contraignante en termes de formes spécifiques de l'anomalie et le degré du polynôme associé, une autre approche traitant la détection des anomalies complètement inconnues est proposée. Les modes glissants d'ordre un et d'ordre supérieur sont conçus pour le modèle TCP pour garantir une convergence en temps fini et la robustesse vis-à-vis des incertitudes paramétriques et des défauts. Nos propositions sont étudiées de manière analytique par des validations sous Matlab/Simulink et le Simulateur de Réseaux NS-2. De plus, dans le contexte de NS-2, ces dernières approches sont intégrées dans un module de rejeu des traces de trafic afin de les tester sur un trafic TCP capturé en environnement réel.
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Argyriou, Antonios D. "Transport Layer Optimizations for Heterogeneous Wireless Multimedia Networks." Diss., Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/7466.
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The explosive growth of the Internet during the last few years, has been propelled by the TCP/IP protocol suite and the best effort packet forwarding service. However, quality of service (QoS) is far from being a reality especially for multimedia services like video streaming and video conferencing. In the case of wireless and mobile networks, the problem becomes even worse due to the physics of the medium, resulting into further deterioration of the system performance.
Goal of this dissertation is the systematic development of comprehensive models that jointly characterize the performance of transport protocols and media delivery in heterogeneous wireless networks. At the core of our novel methodology, is the use of analytical models for driving the design of media transport algorithms, so that the delivery of conversational and non-interactive multimedia data is enhanced in terms of throughput, delay, and jitter. More speciffically, we develop analytical models that characterize the throughput and goodput of the transmission control protocol (TCP) and the transmission friendly rate control (TFRC) protocol, when CBR and VBR multimedia workloads are considered. Subsequently, we enhance the transport protocol models with new parameters that capture the playback buffer performance and the expected video distortion at the receiver. In this way a complete end-to-end model for media streaming is obtained. This model is used as a basis for a new algorithm for rate-distortion optimized mode selection in video streaming appli-
cations. As a next step, we extend the developed models for the aforementioned protocols, so that heterogeneous wireless networks can be accommodated. Subsequently, new algorithms are proposed in order to enhance the developed media streaming algorithms when heterogeneous wireless networks are also included. Finally, the aforementioned models and algorithms are extended for the case of concurrent multipath media transport over several hybrid wired/wireless links.
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Zhu, Jing. "Layer 2 (LL/MAC) performance analysis and improvement of wireless heterogeneous networks /." Thesis, Connect to this title online; UW restricted, 2004. http://hdl.handle.net/1773/5950.
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Pilo-Pais, Albuja Pablo Andres 1987. "Avaliação de desempenho do protocolo TCP-NACK em canais com desvanecimento Rayleigh." [s.n.], 2015. http://repositorio.unicamp.br/jspui/handle/REPOSIP/258817.
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Orientador: Celso de Almeida<br>Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação<br>Made available in DSpace on 2018-08-26T13:55:04Z (GMT). No. of bitstreams: 1
Pilo-PaisAlbuja_PabloAndres_M.pdf: 1954449 bytes, checksum: e3d003c58a69987d3faeca15cf23928f (MD5)
Previous issue date: 2015<br>Resumo: Os enlaces sem fio são propensos a gerar mais erros e perdas de segmentos devido à natureza do desvanecimento neste canal de comunicação. A falta de um mecanismo no protocolo TCP Reno que permita distinguir as perdas por erros aleatórios das perdas por congestionamento, resulta na redução da vazão de dados e um desempenho inferior ao esperado. A fim de melhorar o desempenho do protocolo TCP sobre redes sem fio, uma variante do protocolo TCP que utiliza uma confirmação negativa, NACK, foi proposta previamente em [1] para informar ao transmissor acerca do recebimento de um segmento com erro para sua retransmissão instantânea sem reduzir a janela de congestionamento. Na presente dissertação será avaliado o desempenho do algoritmo TCP-NACK sobre um cenário de provas com desvanecimento Rayleigh. Os resultados mostram que o protocolo TCP-NACK possui melhor desempenho em relação ao protocolo TCP em enlaces sem fio<br>Abstract: Wireless links are prone to generate more errors and segments loss due to the fading nature of the communication channel. The lack of a mechanism in TCP Reno to distinguish random errors from congestion losses, results in throughput reduction and performance lower than expected. In order to improve TCP over wireless networks, a negative acknowledgment, NACK, was earlier proposed in [1] to inform the transmitter about the reception of a segment with error for its retransmission without reducing the congestion window. In this thesis we are going to evaluate the TCP-NACK algorithm over a scenario with Rayleigh fading. The results show that TCP-NACK has better performance over TCP Reno in wireless links<br>Mestrado<br>Telecomunicações e Telemática<br>Mestre em Engenharia Elétrica
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Mirza, Aamir Mehmood, and Mohtashim Khan. "Ethernet Network Functionality Testing." Thesis, Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-3720.
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<p><sup>Ethernet functionality testing as a generic term used for checking connectivity,throughput and capability to transfer packets over the network. Especially in the packet-switchenvironment, Ethernet testing has become an essential part for deploying a reliable network.Over a long distance Ethernet testing parameter for analyzing network performance must havetwo devices attached and synchronized.</sup></p><p>Saab Microwave Systems is among the leading suppliers of radar systems developing groundbased,naval and air-borne radar systems. To ensure the correct functionality, the developerwants to verify the performance of computer network and looking for a suitable solution.</p><p>A software application is required to verify and test the functionality of the Ethernet network andto verify the functionality and performance of the TCP/IP stack of newly added node. Theprograms shall be easily ported to different operating systems and must not depend on specificproduct properties.A software application, <em>“NetBurst”</em>, is developed for Ethernet functionality testing. Theapplication is vendor and platform independent.</p><p><strong> </strong></p>
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Mackie, David Sean. "Extending the reach of personal area networks by transporting Bluetooth communications over IP networks." Thesis, Rhodes University, 2007. http://hdl.handle.net/10962/d1006551.
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This thesis presents an investigation of how to extend the reach of a Bluetooth personal area network by introducing the concept of Bluetooth Hotspots. Currently two Bluetooth devices cannot communicate with each other unless they are within radio range, since Bluetooth is designed as a cable-replacement technology for wireless communications over short ranges. An investigation was done into the feasibility of creating Bluetooth hotspots that allow distant Bluetooth devices to communicate with each other by transporting their communications between these hotspots via an alternative network infrastructure such as an IP network. Two approaches were investigated, masquerading of remote devices by the local hotspot to allow seamless communications and proxying services on remote devices by providing them on a local hotspot using a distributed service discovery database. The latter approach was used to develop applications capable of transporting Bluetooth’s RFCOMM and L2CAP protocols. Quantitative tests were performed to establish the throughput performance and latency of these transport applications. Furthermore, a number of selected Bluetooth services were tested which lead us to conclude that most data-based protocols can be transported by the system.
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Tibor, Sakal. "Metoda za povezivanje mernog sistema i računarapomoću konverzije podataka iz I2S u TCP/IP protokol." Phd thesis, Univerzitet u Novom Sadu, Tehnički fakultet Mihajlo Pupin u Zrenjaninu, 2017. https://www.cris.uns.ac.rs/record.jsf?recordId=103839&source=NDLTD&language=en.
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Ova doktorska disertacija predstavlja istraživački rad sproveden sa ciljem da reši problem koji se odnosi na realizaciju povezivanja laboratorijskog, medicinskog mernog uređaja sa personalnim računarom. Rezultat istraživačkog rada je opšta metoda koja obezbeđuje efikasnu konverziju podataka I2S protokola u TCP/IP protokol.<br>This doctoral thesis presents the research work carried out in order to solve a practical problem, the realization of a connection between a medical measuring device and a personal computer. The result of the research is a general method that provides efficient data conversion from the I2S protocol to the TCP/IP protocol.
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Bamdé, Aurélien. "Essai d'une théorie sur l'architecture normative du réseau Internet." Thesis, Paris 2, 2013. http://www.theses.fr/2013PA020036.
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Complexe : tel est l’adjectif qui, sans aucun doute, résume le mieux la question de l’architecture normative du réseau internet. Complexe, cette question l’est pour deux raisons. La première tient à l’identification des normes qui constituent cette architecture ; la seconde tient à leur objet. Tout d’abord, s’agissant de l’identification de normes, cette entreprise s’avère éminemment complexe dans la mesure où voilà un concept, la norme, qui renvoie à des réalités si différentes, qu’il est peu aisé de le définir. Après avoir établi l’existence de normes qui règlent la conduite des bâtisseurs du réseau, il faudra, en outre, s’interroger sur la nature de ces normes. Là encore, cette problématique n’est pas aussi facile à résoudre qu’il y paraît. Il n’existe, en effet, aucun critère de distinction entre les différentes espèces de normes qui fasse l’unanimité chez les auteurs. Concernant, ensuite, la seconde raison pour laquelle la question de l’architecture normative de l’internet est placée sous le signe de la complexité, c’est vers l’objet des normes qui la composent qu’il conviendra de se tourner : l’organisation de la société numérique. Il s’agit là, d’un système complexe. Si l’on adhère à cette idée, il doit corrélativement être admis que le schéma auquel répondent les normes par l’entremise desquelles le contrôle de pareil système est effectué, est très différent de celui dans lequel s’inscrivent les normes qui nous sont les plus familières : les règles juridiques. Alors que la genèse des premières est sous-tendue par un mécanisme d’auto-organisation, la création des secondes procède d’un acte de volonté. La différence entre les deux schémas est de taille : dans un cas, c’est la spontanéité qui commande la production des règles de conduite, dans l’autre c’est la raison. Dans l’univers numérique, l’opposition entre ces deux schémas normatifs se retrouve : elle se traduit par la concurrence qui existe entre les ordres numériques et juridiques. Aussi, est-ce à travers cette concurrence à laquelle se livrent ces deux systèmes normatifs que sera décrite l’architecture normative du réseau internet<br>Complex is undoubtedly the adjective that best summarises the issue of the normative architecture of the Internet network. This issue is complex for two reasons. The first one results from the identification of the rules that make up this architecture and the second one from their purpose. First of all, the identification of the rules proves to be an extremely complex matter, since this concept of the rule is not so easy to define, as it refers to such a wide range of realities. After establishing the existence of the rules which set the behaviour of network builders, it is necessary to raise the question of the the nature of the rules. Here again, solving this issue is not as easy as it seems. In fact, in literature there is no universal way to distinguish the various types of rules. Secondly, the rules that compose the normative architecture of the internet aim at organising the digital society. Yet, this is a complex system. If one accepts the idea, one has to correlatively claim that the rule-complying scheme that enables such a system to be controlled is very different from that which rules more common rules for us, such as the rules of law. While the former is underpinned by a self organising mechanism, the creation of the latter stems from an act of willing. The difference between both schemes is significant: in the first case spontaneity controls the setting up of rules of conduct, while in the second case reason does. The opposition between these two normative schemes can be found in the digital universe too. It is conveyed by the existing competition between the digital and the legal orders. That is why the normative architecture of the Internet network will be described through the competition between these two normative systems
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Baig, Adeel Computer Science & Engineering Faculty of Engineering UNSW. "Improving throughput and fairness of on-board mobile networks." Awarded by:University of New South Wales. School of Computer Science & Engineering, 2007. http://handle.unsw.edu.au/1959.4/28247.
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The Internet Engineering Task Force (IETF) has recently released network mobility standards that allow deployment of TCP/IP networks onboard a vehicle and maintain permanent network connectivity to the Internet via a vehicular mobile router. This recent development opens up new opportunities for providing efficient mobile computing for users on the move, especially for commuters traveling on public transports. Moreover, central and coordinated management of mobility in a single router, rather than by each user device individually, has numerous advantages. In this architecture, however, it becomes challenging to guarantee network performance due to the mobility of the network and inherently vulnerable nature of wireless links. In this thesis, a detailed performance study of onboard networks is conducted. It has been shown that disruptions in the mobile router connectivity can significantly degrade network throughput. Moreover, factors such as the limited wireless bandwidth of the access link, variations in the bandwidth due to technology switching, and the communication diversity of onboard users all contribute to the problem of unfair sharing of wireless bandwidth. By leveraging the fact that all onboard communications go through the mobile router, performance enhancing solutions are proposed that can be deployed in the mobile router to transparently address the throughput and fairness problems. In this architecture, when the route is known in advance and repetitive (e.g. for public transport or a regularly commuting private vehicle), a certain degree of prediction of impending link disruptions is possible. An anticipatory state freezing mechanism is proposed that relies on the prediction of link disruptions to freeze and unfreeze the state machine of TCP, the widely used transport protocol in the Internet. Simulation study shows that TCP throughput has a non-linear relationship with the prediction accuracy. As prediction accuracy increases, throughput problem diminishes quickly. An adaptive mobile router based fairness control mechanism is proposed to address the unfair sharing of wireless bandwidth in highly dynamic scenarios. The fairness is controlled by dynamically estimating the round-trip-times of all onboard TCP connections and transparently adjusting the protocol control parameters at the router. The thesis also discusses implementation issues for the proposed solutions.
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Garcia, Cristiane Silva. "Ajuste baseado em dados de controladores : o método VRFT embarcado em um aplicativo móvel." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2017. http://hdl.handle.net/10183/163773.
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O método VRFT (Virtual Reference Feedback Tuning) é um método baseado em dados utilizado para ajustar os parâmetros de um controlador. Uma das vantagens deste método é que não é necessário um conhecimento detalhado do modelo do processo a ser controlado. Neste trabalho é apresentado o desenvolvimento de um aplicativo Android que utiliza o método VRFT, e uma versão recursiva do mesmo, para ajustar os parâmetros de um controlador PID com base nos dados de entrada e saída coletados de um experimento realizado no processo. O experimento pode ser configurado, inicializado, monitorado, e interrompido através da aplicação móvel. Para viabilizar a comunicação com o controlador também foram desenvolvidos um gateway Bluetooth-Modbus e um protocolo de comunicação simples, que opera sobre o serviço de comunicação serial do protocolo Bluetooth. A solução proposta foi validada através de experimentos realizados em processos simulados e em um processo real, mostrando bons resultados em ambos os casos.<br>The Virtual Reference Feedback Tuning (VRFT) method is a data-driven method employed to tune the parameters of a controller. An advantage of this method lies in the fact that it does not need a detailed knowledge of the process model. This work presents the development of an Android application which employs the VRFT method and a newly developed recursive version of it to tune a PID controller based upon the data collected from an experiment conducted on the process. The experiment can be set up, started, monitored, and stopped from inside the mobile application. To communicate with the controller a Bluetooth-Modbus gateway and an application layer protocol, designed over the Bluetooth serial communication service, are employed, both newly developed. Finally, the entire solution is verified in two steps: first some experiments were conducted on a simulated process, then another experiment was conducted to tune a real commercial controller, both showing good results.
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Velayutham, Aravind Murugesan. "Transport Protocols for Next Generation Wireless Data Networks." Thesis, Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/6957.
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Emerging wireless networks are characterized by increased heterogeneity in wireless access technologies as well as increased peer-to-peer communication among wireless hosts.
The heterogeneity among wireless access interfaces mainly exists because of the fact that different wireless technologies deliver different performance trade-offs.
Further, more and more infrastructure-less wireless networks such as ad-hoc networks are
emerging to address several application scenarios including military and disaster recovery. These infrastructure-less wireless networks are characterized by the peer-to-peer communication
model. In this thesis, we propose transport protocols that tackle the challenges that arise
due to the above-mentioned properties of state-of-the-art wireless data networks.
The main contributions of this work are as follows:
1. We determine the ideal nature and granularity of transport adaptation for efficient operation in heterogeneous wireless data networks by performing comprehensive experimental analysis. We then design and implement a runtime adaptive transport framework, *TP, which accommodates the capabilities of the ideal transport adaptation solution.
2. We prove that conversational transport protocols are not efficient under peer-to-peer wireless data networks. We then design and implement NCTP which is a non-conversational transport protocol.
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Oliveira, Carlos Henrique Rodrigues de. "Analise de desempenho dos sistemas moveis celulares 2G, 2,5G e 3G." [s.n.], 2005. http://repositorio.unicamp.br/jspui/handle/REPOSIP/260571.
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Orientador: Renato Baldini Filho<br>Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação<br>Made available in DSpace on 2018-08-05T14:02:39Z (GMT). No. of bitstreams: 1
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Previous issue date: 2005<br>Resumo: Este trabalho de tese estuda e analisa o desempenho dos sistemas móveis celulares GSM de segunda geração (2G), GPRS de segunda geração intermediária (2,5G) e CDMA2000 de terceira geração (3G). Na primeira parte deste trabalho de tese são avaliadas estratégias de compartilhamento dos canais de comunicação utilizados pelos sistemas GSM e GPRS, em busca daquela que resulte no menor impacto na qualidade dos serviços prestados por ambas as redes. Para esta avaliação, e como contribuição deste trabalho de tese, são desenvolvidos algoritmos aplicados em um simulador de eventos discretos desenvolvido em linguagem de programação C/C++. Os resultados das simulações mostram que a reserva de canais exclusivos ao sistema GPRS apresenta degradação na qualidade de serviço prestado pelo sistema GSM e que a melhor estratégia de compartilhamento é utilizar os canais de comunicação para o sistema GPRS nos momentos em que estes canais não são usados pelo sistema GSM. Na segunda parte deste trabalho de tese são feitas análises de desempenho dos sistemas móveis celulares de terceira geração, CDMA2000 lxRTT e CDMA2000 lxEVDO, baseadas na qualidade do serviço prestado por estas redes operando com várias aplicações simultâneas fim-a-fim entre cliente e servidor. Técnicas de detecção multiusuário e de antenas adaptativas são utilizadas na recepção destas aplicações e é avaliada a nova qualidade de serviço. Para estas análises de desempenho e como contribuição deste trabalho de tese, modelos de simulação são desenvolvidos utilizando a ferramenta OPNET. As redes CDMA2000 lxRTT e lxEVDO apresentam bom desempenho, analisado pelo parâmetro atraso da qualidade de serviço, na passagem de tráfego das aplicações HTTP, E-mail, VoIP, FTP, Telnet e Acesso a Banco de Dados. O desempenho da rede CDMA2000 lxEVDO melhora tanto com detecção multiusuário como com antenas adaptativas em relação ao receptor rake<br>Abstract: This thesis work studies and analyzes the performance of cellular mobile systems GSM of second generation (2G), GPRS of second intermediate generation (2,5G) and CDMA2000 of third generation (3G). In the first part of this thesis work, sharing strategies of communication channels used by GSM and GPRS systems are evaluated to find the one that results in the lowest impact in the quality of services supported by both networks. To this evaluation, and as contribution of this thesis work, algorithms applied in a discrete-event simulator developed in C/C++ programming language are developed. The simulation results show that the reserve of exclusive channels to the GPRS system presents degradation in the quality of service given for GSM system and that the better sharing strategy is to use the communication channels for the GPRS system whenever these channels are not used by the GSM system. In the second part of this thesis work, performance analyses of the third generation cellular mobile systems, CDMA2000 lxRTT and CDMA2000 lxEVDO, based on the quality of service supported by these networks operating with several end-to-end simultaneous applications between client and server are made. Multiuser detection and adaptive antennas techniques are used in the reception of these applications and the new quality of service is evaluated. For these performance analyses, and as contribution of this thesis work, simulation models are developed using the OPNET tool. The CDMA2000 lxRTT and lxEVDO networks present good performance analyzed through the delay parameter of quality of service running HTTP, E-mail, VolP, FTP, Telnet and Data Base Access applications. The CDMA2000 lxEVDO network performance improves using either multiuser detection or adaptive antennas when compared with rake receiver<br>Doutorado<br>Telecomunicações e Telemática<br>Doutor em Engenharia Elétrica
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Adams, Richelle Vive-Anne. "Infinitesimal Perturbation Analysis for Active Queue Management." Diss., Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/19844.
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Active queue management (AQM) techniques for congestion control in Internet Protocol (IP) networks have been designed using both heuristic and analytical methods. But so far, there has been found no AQM scheme designed in the realm of stochastic optimization. Of the many options available in this arena, the gradient-based stochastic approximation method using Infintesimal Perturbation Analysis (IPA) gradient estimators within the Stochastic Fluid Model (SFM) framework is very promising. The research outlined in this thesis provides the theoretical basis and foundational layer for the development of IPA-based AQM schemes. Algorithms for computing the IPA gradient estimators for loss volume and queue workload were derived for the following cases: a single-stage queue with instantaneous, additive loss-feedback, a single-stage queue with instantaneous, additive loss-feedback and an unresponsive competing flow, a single-stage queue with delayed, additive loss-feedback, and a multi-stage tandem network of $m$ queues with instantaneous, additive loss-feedback. For all cases, the IPA gradient estimators were derived with the control parameter, $ heta$, being the buffer-limits of the queue(s). For the single-stage case and the multi-stage case with instantaneous, additive loss-feedback, the IPA gradient estimators for when the control parameter, $ heta$, is the loss-feedback constant, were also derived. Sensitivity analyses and optimizations were performed with control parameter, $ heta$, being the buffer-limits of the queue(s), as well as the loss-feedback constant.
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Opie, Jake Weyman. "Securing softswitches from malicious attacks." Thesis, Rhodes University, 2007. http://hdl.handle.net/10962/d1007714.
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Traditionally, real-time communication, such as voice calls, has run on separate, closed networks. Of all the limitations that these networks had, the ability of malicious attacks to cripple communication was not a crucial one. This situation has changed radically now that real-time communication and data have merged to share the same network. The objective of this project is to investigate the securing of softswitches with functionality similar to Private Branch Exchanges (PBX) from malicious attacks. The focus of the project will be a practical investigation of how to secure ILANGA, an ASTERISK-based system under development at Rhodes University. The practical investigation that focuses on ILANGA is based on performing six varied experiments on the different components of ILANGA. Before the six experiments are performed, basic preliminary security measures and the restrictions placed on the access to the database are discussed. The outcomes of these experiments are discussed and the precise reasons why these attacks were either successful or unsuccessful are given. Suggestions of a theoretical nature on how to defend against the successful attacks are also presented.
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Cesário, Júnior José Maria 1979. "Um medidor de energia elétrica integrado em redes de comunicações." [s.n.], 2014. http://repositorio.unicamp.br/jspui/handle/REPOSIP/267697.
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Orientadores: Varese Salvador Timóteo, Francisco José Arnold<br>Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Tecnologia<br>Made available in DSpace on 2018-08-24T09:10:01Z (GMT). No. of bitstreams: 1
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Previous issue date: 2014<br>Resumo: A crescente evolução mundial dos sistemas de medição inteligentes, a liberação de regulamentações Brasileiras, incentivando a adoção de sistemas de medição de energia elétrica inteligentes, direcionaram a presente dissertação a propor um sistema composto de um equipamento eletrônico para medição, em tempo real, das grandezas de corrente, tensão e calcular a energia consumida e terá canais de comunicação com as tecnologias Wi-Fi, GSM/GPRS e GPS. As informações sobre consumo serão disponibilizadas para os usuários finais com o objetivo de mudar o padrão de consumo de energia elétrica, ou até reduzi-lo, através da conscientização e disponibilização das informações de consumo em tempo real<br>Abstract: The growing worldwide trend of smart metering systems, the release of Brazilian regulations, encouraging the adoption of smart electricity metering systems, guided this dissertation to propose a system composed of an electronic device for measuring, in real time, the magnitudes of current, voltage and calculate the consumed power and will have communication channels based on Wi-Fi, GSM /GPRS and GPS technologies. The consumption information will be made available to end users with the goal of changing the electricity consumption pattern, or even reduce it, through awareness and provision of consumer information in real time<br>Mestrado<br>Tecnologia e Inovação<br>Mestre em Tecnologia
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Dolphine, Tiago Marchetti. "Plataforma de serviços de infra-estrutura para arquiteturas de mobilidade." [s.n.], 2009. http://repositorio.unicamp.br/jspui/handle/REPOSIP/258965.
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Orientador: Eleri Cardozo<br>Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação<br>Made available in DSpace on 2018-08-14T03:43:39Z (GMT). No. of bitstreams: 1
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Previous issue date: 2009<br>Resumo: Arquiteturas de micromobilidade vêm sendo propostas para atender ao crescente interesse por tecnologias de mobilidade IP. MPA (Mobility Plane Architecture), desenvolvida na FEEC/Unicamp, é uma solução de micromobilidade baseada em tunelamento de pacotes que emprega apenas protocolos bem estabelecidos. Quando estudou-se aplicações para melhoria de desempenho em handover e engenharia de tráfego na arquitetura MPA, verificou-se que estas aplicações necessitavam serviços comuns. Este trabalho descreve a plataforma MIS (Mobility Infrastructure Services) que fornece um conjunto de serviços para suporte ás funcionalidades básicas comuns de aplicações de gerência de rede, engenharia de tráfego e gerência de mobilidade. A plataforma proposta facilita o desenvolvimento de tais aplicações compartilhando soluções às necessidades encontradas na arquitetura de micromobilidade MPA e outras arquiteturas similares. São apresentados o projeto, implementação e testes da plataforma, juntamente com dois estudos de casos em gerência de mobilidade e engenharia de tráfego. Palavras-chave: redes IP móveis, micromobilidade, gerência de rede, engenharia de tráfego<br>Abstract: Micro-mobility architectures have been proposed to meet the growing interest in technologies supporting mobility in IP networks. MPA (Mobility Plane Architecture), developed at the FEEC/Unicamp, is a micro-mobility solution based on tunneling of packets that employs only well standardized protocols. When applications for supporting seamless handover and traffic engineering in MPA started to be designed, it was noticed that these applications demand a set of common services. This dissertation presents the MIS (Mobility Infrastructure Services) platform which provides a set of services that meet the common basic features demanded by applications of network management, traffic engineering and mobility management. The proposed platform facilitates the development of these applications when they are targeted to MPA and other micro-mobility architectures. This dissertation reports the design, implementation, ant test of the MIS platform, along with two case studies in mobility management and traffic engineering. Keywords: IP mobile networks, micro-mobility, network management, traffic engineering<br>Mestrado<br>Engenharia de Computação<br>Mestre em Engenharia Elétrica
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Nunes, Fábio Pessoa. "Arquitetura de mobilidade IPv6 entre cidades digitais = Mobile IPv6 architecture between digital cities." [s.n.], 2012. http://repositorio.unicamp.br/jspui/handle/REPOSIP/259452.
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Orientador: Leonardo de Souza Mendes<br>Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação<br>Made available in DSpace on 2018-08-21T21:10:42Z (GMT). No. of bitstreams: 1
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Previous issue date: 2012<br>Resumo: O resumo poderá ser visualizado no texto completo da tese digital<br>Abstract: The abstract is available with the full electronic document<br>Mestrado<br>Telecomunicações e Telemática<br>Mestre em Engenharia Elétrica
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Wang, Lan. "Performance modeling of congestion control and resource allocation under heterogeneous network traffic : modeling and analysis of active queue management mechanism in the presence of poisson and bursty traffic arrival processes." Thesis, University of Bradford, 2010. http://hdl.handle.net/10454/4455.
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Along with playing an ever-increasing role in the integration of other communication networks and expanding in application diversities, the current Internet suffers from serious overuse and congestion bottlenecks. Efficient congestion control is fundamental to ensure the Internet reliability, satisfy the specified Quality-of-Service (QoS) constraints and achieve desirable performance in response to varying application scenarios. Active Queue Management (AQM) is a promising scheme to support end-to-end Transmission Control Protocol (TCP) congestion control because it enables the sender to react appropriately to the real network situation. Analytical performance models are powerful tools which can be adopted to investigate optimal setting of AQM parameters. Among the existing research efforts in this field, however, there is a current lack of analytical models that can be viewed as a cost-effective performance evaluation tool for AQM in the presence of heterogeneous traffic, generated by various network applications. This thesis aims to provide a generic and extensible analytical framework for analyzing AQM congestion control for various traffic types, such as non-bursty Poisson and bursty Markov-Modulated Poisson Process (MMPP) traffic. Specifically, the Markov analytical models are developed for AQM congestion control scheme coupled with queue thresholds and then are adopted to derive expressions for important QoS metrics. The main contributions of this thesis are listed as follows: • Study the queueing systems for modeling AQM scheme subject to single-class and multiple-classes Poisson traffic, respectively. Analyze the effects of the varying threshold, mean traffic arrival rate, service rate and buffer capacity on the key performance metrics. • Propose an analytical model for AQM scheme with single class bursty traffic and investigate how burstiness and correlations affect the performance metrics. The analytical results reveal that high burstiness and correlation can result in significant degradation of AQM performance, such as increased queueing delay and packet loss probability, and reduced throughput and utlization. • Develop an analytical model for a single server queueing system with AQM in the presence of heterogeneous traffic and evaluate the aggregate and marginal performance subject to different threshold values, burstiness degree and correlation. • Conduct stochastic analysis of a single-server system with single-queue and multiple-queues, respectively, for AQM scheme in the presence of multiple priority traffic classes scheduled by the Priority Resume (PR) policy. • Carry out the performance comparison of AQM with PR and First-In First-Out (FIFO) scheme and compare the performance of AQM with single PR priority queue and multiple priority queues, respectively.
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"TCP Reno over adaptive CSMA." 2010. http://library.cuhk.edu.hk/record=b5894411.
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Chen, Wei.<br>Thesis (M.Phil.)--Chinese University of Hong Kong, 2010.<br>Includes bibliographical references (leaves 64-67).<br>Abstracts in English and Chinese.<br>Dedication --- p.iv<br>Chapter 1 --- Introduction --- p.1<br>Chapter 1.1 --- Motivation --- p.1<br>Chapter 1.2 --- Contributions --- p.2<br>Chapter 1.3 --- Thesis Organization --- p.3<br>Chapter 2 --- Related Work --- p.4<br>Chapter 2.1 --- Previous Work on Rate Control and link Scheduling in Wireless Networks --- p.4<br>Chapter 2.2 --- Previous Work on Multi-connection TCP --- p.6<br>Chapter 2.3 --- Previous Work on AQM --- p.6<br>Chapter 3 --- Problem Settings --- p.7<br>Chapter 3.1 --- Network Modeling --- p.7<br>Chapter 3.2 --- Capacity Region of Wireless Networks and Throughput-optimal Scheduling --- p.9<br>Chapter 3.3 --- Throughput-optimality of A-CSMA --- p.10<br>Chapter 3.4 --- TCP Reno Congestion Control Modeling --- p.11<br>Chapter 4 --- Starvation of TCP Reno over L-CSMA and A-CSMA --- p.13<br>Chapter 4.1 --- TCP Reno Starves over L-CSMA --- p.13<br>Chapter 4.2 --- TCP Reno Starves over A-CSMA --- p.15<br>Chapter 4.2.1 --- Simulations --- p.15<br>Chapter 4.2.2 --- Observations and Explanations --- p.17<br>Chapter 5 --- Analysis and Our Proposed Solution --- p.19<br>Chapter 5.1 --- Proposed Solution: Multi-connection TCP Reno Scheme --- p.19<br>Chapter 5.2 --- Implementation --- p.25<br>Chapter 5.3 --- Discussion --- p.28<br>Chapter 5.3.1 --- Achieve Arbitrary Utility --- p.28<br>Chapter 5.3.2 --- Extension to Networks with Both Wired and Wireless Links --- p.28<br>Chapter 5.3.3 --- Impact of ACK Traffic --- p.30<br>Chapter 5.3.4 --- Tradeoff between performance and overhead --- p.31<br>Chapter 5.3.5 --- Overhead of Multi-connection TCP --- p.32<br>Chapter 6 --- Simulations --- p.37<br>Chapter 6.1 --- Single-hop Wireless Networks Scenario --- p.38<br>Chapter 6.1.1 --- Fairness and Throughput --- p.38<br>Chapter 6.1.2 --- Impact of Measuring Queue Length in Number of Bytes for n-ACK --- p.42<br>Chapter 6.1.3 --- Impact of Dummy Packets --- p.43<br>Chapter 6.1.4 --- Impact of Product k2β --- p.45<br>Chapter 6.1.5 --- Effects of Parameterβ --- p.47<br>Chapter 6.1.6 --- Effects of Parameter k --- p.49<br>Chapter 6.1.7 --- Overhead of n-ACK Solution --- p.50<br>Chapter 6.2 --- Multihop Wireless Networks Scenario --- p.52<br>Chapter 6.3 --- Multihop Networks with Wireless and Wired Links Scenario --- p.53<br>Chapter 7 --- Conclusions and Future Work --- p.56<br>Chapter 7.1 --- Conclusions --- p.56<br>Chapter 7.2 --- Future Work --- p.57<br>Chapter A --- Explanation to Starvation of TCP Reno over A-CSMA --- p.58<br>Chapter B --- TCP Reno over A-CSMA with AQM --- p.60<br>Chapter B.1 --- TCP Reno starves --- p.60<br>Chapter B.2 --- Explanation --- p.61<br>Bibliography --- p.64
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"Transport layer optimization for mobile data networks." 2010. http://library.cuhk.edu.hk/record=b5894706.
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Wan, Wing San.<br>"September 2010."<br>Thesis (M.Phil.)--Chinese University of Hong Kong, 2010.<br>Includes bibliographical references (p. 53-55).<br>Abstracts in English and Chinese.<br>Acknowledgements --- p.ii<br>Abstract --- p.iii<br>摘要 --- p.iv<br>Contents --- p.v<br>Chapter Chapter 1 --- INTRODUCTION --- p.1<br>Chapter Chapter 2 --- BACKGROUND AND RELATED WORK --- p.4<br>Chapter 2.1 --- Sender-receiver-based approaches --- p.4<br>Chapter 2.2 --- Sender-based approaches --- p.5<br>Chapter 2.3 --- Receiver-based approaches --- p.6<br>Chapter Chapter 3 --- TCP FLOW CONTROL REVISITED --- p.8<br>Chapter Chapter 4 --- OPPORTUNISTIC TRANSMISSION --- p.12<br>Chapter 4.1 --- Link bandwidth estimation --- p.16<br>Chapter 4.2 --- Reception rate estimation --- p.18<br>Chapter 4.3 --- Transmission scheduling --- p.19<br>Chapter 4.4 --- Performance --- p.21<br>Chapter Chapter 5 --- Local Retransmission --- p.23<br>Chapter 5.1 --- The blackout period --- p.24<br>Chapter 5.2 --- Proactive retransmission --- p.28<br>Chapter 5.3 --- Performance --- p.30<br>Chapter Chapter 6 --- Loss Event Suppression --- p.31<br>Chapter 6.1 --- RTT modulation --- p.32<br>Chapter 6.2 --- Performance --- p.35<br>Chapter Chapter 7 --- Fairness --- p.37<br>Chapter 7.1 --- Packet forwarding --- p.37<br>Chapter 7.2 --- Non-uniform bandwidth allocation --- p.41<br>Chapter Chapter 8 --- EXPERIMENTS --- p.43<br>Chapter 8.1 --- Experiment setup --- p.43<br>Chapter 8.2 --- Packet loss --- p.44<br>Chapter 8.3 --- Unaccelerated TCP throughput --- p.45<br>Chapter 8.4 --- Accelerated TCP throughput --- p.46<br>Chapter 8.5 --- Fairness --- p.47<br>Chapter 8.6 --- Mobile handset performance --- p.47<br>Chapter Chapter 9 --- FUTURE WORK --- p.49<br>Chapter 9.1 --- Dynamic AWnd control --- p.49<br>Chapter 9.2 --- Split-TCP --- p.50<br>Chapter 9.3 --- Dynamic resource allocation --- p.50<br>Chapter 9.4 --- Sender-based acceleration --- p.51<br>Chapter Chapter 10 --- CONCLUSION --- p.52<br>BIBLIOGRAPHY --- p.53
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Anand, Kunde. "Providing QoS To Real-time And Data Applications In 3G Wireless Systems." Thesis, 2008. http://hdl.handle.net/2005/795.
Full textAbstract:
In this thesis we address the problem of providing end-to-end quality of service (QoS) to real-time and data connections in a third generation (3G) cellular network based on the Universal Mobile Telecommunication System (UMTS) standard.
Data applications usually use TCP (Transmission Control Protocol) and the QoS is a minimum guaranteed mean throughput. For this one first needs to compute the throughput of a TCP connection sending its traffic through the UMTS network (possibly also through the wired part of the Internet). Thus we obtain closed form expressions for a TCP throughput in a UMTS environment. For downloading data at a mobile terminal, the packets of each TCP connection are stored in separate queues at the base station (node B). These are fragmented into Protocol Data Units (PDU). The link layer uses ARQ (Automatic Repeat Request). Thus there can be significant random transmission/queueing delays of TCP packets at the node B. On the other hand the link may not be fully utilized due to the delays of the TCP packets in the rest of the network. In such a scenario the existing models of TCP may not be sufficient. Thus we provide new approximate models for TCP and also obtain new closed form expressions of mean window size. Using these we obtain the throughput of a TCP connection for the scenario where the queueing delays are non-negligible compared to the overall Round Trip Time (RTT) and also the link utilization is less than one. Our approximate models can be useful not only in the UMTS context but also else where.
In the second half of the thesis, we use these approximate models of TCP to provide minimum mean throughput to data connections in UMTS. We also consider real-time applications such as voice and video. These can tolerate a little packet loss (~1%) but require an upper Bound on the delay and delay jitter (≤ 150 ms). Thus if the network provides a constant bandwidth and the received SINR is above a specified threshold ( with a certain probability), QoS for the real-time traffic will be satisfied.
The 3G cellular systems are interference limited. Thus wise allocation of power is critical in these systems. Hence we consider the problem of providing end-to-end QoS to different users along with the minimization of the downlink power allocation.
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Huang, Xiao-Zhen, and 黃筱真. "Honeypot-based Intrusion Detection Method Using LSTM for Modbus TCP Protocol." Thesis, 2019. http://ndltd.ncl.edu.tw/cgi-bin/gs32/gsweb.cgi/login?o=dnclcdr&s=id=%22107NCHU5394041%22.&searchmode=basic.
Full textAbstract:
碩士<br>國立中興大學<br>資訊科學與工程學系所<br>107<br>Industrial Control Systems (ICS) are often used in critical infrastructures such as energy, water resources, chemical, manufacturing, and transportation. With the development of information communication technologies, ICS faces more and more cyber-attack risks. Intrusion Detection System (IDS) is a commonly used approach to improve the security of ICS, and honeypot techniques are very useful in collecting hacker behavior data in ICS.
In this thesis, a honeypot-based intrusion detection method using Long Short- Term Memory (LSTM) neural network for Modbus TCP protocol is proposed. Honeypot is a technique that is used to capture malicious data by pretending the real system. Honeypots can be classified into either low-interaction honeypots or high-interaction honeypots. Low-interaction honeypot is easy to develop and deploy, but it is easy to be recognized by hacker or by ICS search engine like Shodan. On the other hand, high-interaction honeypot is more difficult to be recognized because it provides more complicated features of devices with high interaction capabilities. Physical honeypot is regarded as an implementation of high-interaction honeypot by using real device to lure hackers. In this thesis, we build a Modbus TCP physical honeypot to capture malicious data.
In the proposed intrusion detection model, both normal and malicious data are used in training. In the preprocessing phase, the log data are transformed from packets into session data. Because the network packets in ICS network have strong temporal relationship, LSTM neural network and ensemble method are used to improve the performance of the proposed intrusion detection method. The experimental results show that the accuracy for detecting Modbus TCP attacks is about 92%.
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ChenTzu-Kao and 高振哲. "Adaptive TCP protocol for wireless communication systems." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/a72fm9.
Full textAbstract:
碩士<br>國立交通大學<br>電子工程系所<br>92<br>Supporting heterogeneous services are mandatory for 3G and beyond wireless systems. Using the wireline data transmission protocol might not be suitable for wireless systems. In this thesis, we will identify potential TCP performance problems in wireless environment where the transmission bandwidth is varied and errors are bursty. An Adaptive Timer-based control algorithm is proposed to improve the TCP performance in wireless communication systems.
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Wang, Pin-Han, and 王品翰. "An Intrusion Detection Method Based on Log Sequence Clustering of Honeypot for Modbus TCP Protocol." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/972urv.
Full textAbstract:
碩士<br>國立中興大學<br>資訊科學與工程學系<br>106<br>Modbus TCP protocol is a famous and widely used industrial communication protocol for industrial control systems (ICSs). With the increasing number of attacks on ICSs, the protection of industrial network has become an important issue. For preventing ICSs from being hacked, one of efficient way is developing intrusion detection methods for Modbus TCP. In this thesis, we consider three problems of the intrusion detection methods: (1) Intrusion detection methods for Modbus TCP should detect attack behaviors with sequential feature. (2) They should detect as much as possible attacks, even including unexpected ones. (3) They should provide clear representation for detected Modbus TCP attacks. For solving these problems, we propose an intrusion detection method using honeypot for Modbus TCP protocol.
In the proposed method, the log file of a honeypot on Modbus TCP protocol consists of Modbus TCP instruction sequences communicated between the honeypot and other nodes. Due to the characteristics of honeypot systems, all of the recorded sequences can be treated as attack behaviors. The proposed method then analyzes the log sequences in the following steps: (1) A similarity function based on longest common subsequence is defined for log sequences. (2) A hierarchical clustering method is then applied to cluster the log sequences. (3) For each cluster, it will extract representative instruction sequence to represent the type of attacks. (4) Finally, the proposed method will generate the flow graph (FG) to show the interaction flow for each representative attacks. The proposed method provides deep analysis for detecting Modbus TCP attacks and unexpected ones. It also uses FGs to visualize the attack behaviors.
The proposed method was implemented using the open-source honeypot called Conpot to collect attack behaviors on Modbus. The experimental results revealed that the proposed method has 88% accuracy for identifying attack behaviors, and can detect unexpected ones at 92% true positive and 0% false positive rates.
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Jaya, Ali, and 王慶吉. "Study of a Configurable Wireless Sensor Module Using Modbus TCP Protocol and User Defined Environment Development." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/70749254256265291149.
Full textAbstract:
碩士<br>國立臺灣科技大學<br>自動化及控制研究所<br>104<br>Traditional sensors using analogue output are still used in many industry applications. The variety output such as ampere and voltage communication make sensors need some device to make a smart sensors. To bridge the technology between the traditional sensors and the smart sensors, a configurable wireless sensor platform is proposed in this study. This study will focus on for sensors with voltage output, and modification output from current to voltage. Universal sensors can be applied because service in android for user configuration in the smartphone will give opportunity to attach many type sensors. Modbus TCP using wireless media communication which has IEEE802.11 standard will be used for communicate between smart sensors and smartphone. By applying this method, a traditional sensor acts as though smart sensor which has capability of “plug and play” and connects to the network. The System provides user defined environment which may accommodate user’s need for flexible application. Main functions are for data acquisition to monitor, to record and to report physical properties through a smartphone with android system. Several analog output such as THS24 humidity sensor and LM35 temperature sensor were used for measuring in lab room, data can be displayed and can be transferred through email for further analysis.
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HSIAO, TZU-CHIEH, and 蕭子傑. "The Study of Heartbeat Monitoring and Warning System Based on Modbus Communication Protocol." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/ccn294.
Full textAbstract:
碩士<br>國立臺北教育大學<br>資訊科學系碩士班<br>107<br>The field of physiological information collection is an important indicator in Medical Sciences .Among them ,obtaining physiological signals recording , calculating and even alerting is one of the major themes that technology assisted in medical sciences .The purpose of how to get physiological signals is to use the sensing elements to convert the signals into common electrical signals .Cause of these signal which are easy to be measure , track and log can help bioinformatics and family medicine .In the existing literatures , researches and the development of instruments , there are lots of cases that scholars have proposed that the theory records such physiological information into electrical signals , but such of tracking and control these of important parts are regularly be ignored . Asthe process of the wafer is improved , so that sensor chip being tiny enable to be carried around . As long as they have such instruments , lots of physiological information can be obtained, add the alert system and control system , let the system be a precision instrument which track our body information and alarm if needs . In addition , in the experiments we designed and implemented , using the industry’s open andrigorous Modbus communication protocol , the best of it’s feature is that each package will be calculated by cyclic redundancy after transmission , improving the correctness of data and reducing the incidence of wrong alarms , while supporting wired and wireless transmission formats , the protocol makes the system more widely used . This experiment will use the Modbus protocol for data transmission and using photoplethysmography to tracing heartbeat and alarm accidents by system.
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HUANG, WEI-CHENG, and 黃韋程. "Design of Renewable Energy Management System Based on DNP3.0 and Modbus Communication Protocol." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/76930524970897389529.
Full textAbstract:
碩士<br>國立高雄應用科技大學<br>電機工程系博碩士班<br>105<br>In order to improve renewable energy utilization and maintain power supply quality in distribution system, this paper investigates the principle of renewable energy regulation and replaces the traditional inverter by the smart inverter which has voltage control strategies for solar photovoltaic (PV) systems. The smart inverters can enhance the renewable energy grid capacity and power quality effectively. The study proposes a communication unit to convert data between Distributed Network Protocol (DNP3.0) and Modbus protocol for developing a communication bridge between PV systems and Taipower. The communication unit is integrated in the renewable energy management system (REMS) for supervisory control and data acquisition (SCADA).The REMS executes remote control of PV inverters to prevent the overvoltage problem. Several PV systems in Yunlin District of Taipower are selected for practical tests to verify the effectiveness of the proposed system.
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"TCP performance over mobile data networks." 2013. http://library.cuhk.edu.hk/record=b5549819.
Full textAbstract:
近年來，使用者通過移動數據網路，如3G和LTE，連接到互聯網的數目急劇增加。眾所周知無線網路和移動數據網路展現的特點和有線網路有很大的不同。儘管如此，大多數移動應用程式的基本構建塊，即傳輸控制協議（TCP），在很大程度上仍是根植於有線網路。本論文通過廣泛的開展多個移動數據網路，包括3G，HSPA，最新的LTE網路的測試和實驗，探討TCP在現代移動數據網路的性能。儘管移動數據網路頻寬的迅速增加，我們的測量結果均顯示，現有的TCP實現在實踐中表現不佳，未能利用高速移動數據網路豐富的頻寬。這項工作解決TCP的性能限制，採用一種新的方法透明協議優化，通過在中間網路設備即時優化TCP，顯著提高TCP的吞吐量。具體來說，這項工作發展（一）一個新穎的機會傳輸算法克服TCP的流量控制的瓶頸;（二）一個傳輸速率控制演算法來解決TCP的拥塞控制的瓶頸;（三）一個新穎的投機重傳演算法，以提高TCP在重傳中的吞吐量;（四）用隨機模型來量化TCP吞吐量性能對移動網路資源利用率的影響;（五）一個新的隊列長度測量算法，為擁塞控制和網路監測打開一條新的途徑。另外，擬議的協議優化技術已全面實施，變成一個移動加速器裝置已經成功在三個不同的3G/LTE生產移動數據網路領域試用，實驗顯示TCP的吞吐量從48%增加至163%。在發明一種新的傳輸協議，或修改現有的TCP實施相比，所提出的方法不要求在用戶端/伺服器的主機現有的TCP實施任何修改，不需要重新配置伺服器或用戶端，並因此可以容易在現今的3G和4G移動網路部署，提高所有現有網路上運行在TCP之上的應用程式的吞吐量性能。<br>The number of Internet users which are connected via mobile networks such as 3G and LTE has increased dramatically in recent years. It is well-known that wireless networks in general, and mobile data networks in particular, exhibit characteristics that are very different from their wired counterparts. Nevertheless, the fundamental building block of most Internet applications, namely the Transmission Control Protocol (TCP), is still largely rooted in wired networks. This dissertation investigate the performance of TCP over modern mobile data networks through extensive measurements and experiments carried out in multiple production data networks, ranging from 3G, HSPA, to the latest LTE networks. Despite the rapid increases in mobile network bandwidth, our measurements consistently reveal that existing TCP implementations perform sub-optimally in practice, failing to utilize the abundant bandwidth available in high-speed mobile networks. This work tackles the performance limitations of TCP using a novel approach - transparent protocol optimization, to significantly improve TCP’s throughput performance using on-the-fly protocol optimization carried out by an intermediate network device in-between the TCP end-hosts. Specifically, this work develops (i) a novel opportunistic transmission algorithm to overcome the TCP’s flow control bottleneck; (ii) a transmission rate control algorithm to tackle TCP’s congestion control bottleneck; (iii) a new opportunistic retransmission algorithm to improve TCP’s performance during packet loss recovery; (iv) a stochastic model to quantify the impact of TCP throughput performance on mobile network capacity; and (v) a new queue length estimation algorithm which opens a new avenue for congestion control and network monitoring. In addition, the proposed protocol optimization techniques have been fully implemented into a mobile accelerator device which has been successfully field trialed in three different production 3G/LTE mobile networks, consistently increasing TCP’s throughput by 48% to 163%. In contrast to inventing a new transport protocol or modifying an existing TCP implementation, the proposed approach does not require any modification to the existing TCP implementation at the client/server hosts, does not require any reconfiguration of the server or client, and hence can be deployed readily in today’s 3G and 4G mobile networks, raising the throughput performance of all existing network applications running atop TCP.<br>Detailed summary in vernacular field only.<br>Liu, Ke.<br>Thesis (Ph.D.)--Chinese University of Hong Kong, 2013.<br>Includes bibliographical references (leaves 166-174).<br>Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web.<br>Abstracts also in Chinese.<br>Abstract --- p.2<br>Acknowledgement --- p.6<br>Chapter 1 --- p.1<br>Introduction --- p.1<br>Chapter 1.1 --- Motivation --- p.1<br>Chapter 1.2 --- Contributions --- p.3<br>Chapter 1.3 --- Structure of the Thesis --- p.6<br>Chapter 2 --- p.9<br>Flow and Congestion Control --- p.9<br>Chapter 2.1 --- TCP Performance Bottlenecks --- p.9<br>Chapter 2.2 --- Background and related works --- p.16<br>Chapter 2.3 --- Transparent Protocol Optimization --- p.20<br>Chapter 2.3.1 --- Opportunistic Transmission --- p.20<br>Chapter 2.3.2 --- Transmission Rate Control --- p.22<br>Chapter 2.3.3 --- Lost Packet Recovery --- p.27<br>Chapter 2.4 --- Modeling and Analysis --- p.28<br>Chapter 2.4.1 --- Background and Assumptions --- p.28<br>Chapter 2.4.2 --- Queue Length at the Radio Interface --- p.31<br>Chapter 2.4.3 --- Queue Length Bounds --- p.38<br>Chapter 2.4.4 --- Guaranteeing Full Bandwidth Utilization --- p.45<br>Chapter 2.4.5 --- Link Buffer Size Requirement --- p.47<br>Chapter 2.5 --- Performance Evaluation --- p.53<br>Chapter 2.5.1 --- Parameter Tuning --- p.53<br>Chapter 2.5.2 --- Bandwidth Efficiency --- p.56<br>Chapter 3 --- p.62<br>Packet Loss Recovery --- p.62<br>Chapter 3.1 --- Introduction --- p.62<br>Chapter 3.2 --- TCP Loss Recovery Revisited --- p.64<br>Chapter 3.2.1 --- Standard TCP Loss Recovery Algorithm --- p.64<br>Chapter 3.2.2 --- Loss Recovery Algorithm in Linux --- p.66<br>Chapter 3.2.3 --- Loss Recovery Algorithm in A-TCP --- p.67<br>Chapter 3.3 --- Efficiency of TCP Loss Recovery Algorithms --- p.68<br>Chapter 3.3.1 --- Standard TCP Loss Recovery Algorithm --- p.70<br>Chapter 3.3.2 --- TCP Loss Recovery in Linux --- p.72<br>Chapter 3.3.3 --- Loss Recovery Algorithm Used in A-TCP --- p.72<br>Chapter 3.3.4 --- Discussions --- p.73<br>Chapter 3.4 --- Opportunistic Retransmission --- p.74<br>Chapter 3.4.1 --- Applications and Performance Analysis --- p.76<br>Chapter 3.4.2 --- Bandwidth Utilization During Loss Recovery --- p.78<br>Chapter 3.5 --- Experimental Results --- p.81<br>Chapter 3.5.1 --- Model Validation --- p.85<br>Chapter 3.5.2 --- Impact of Loss Recovery Phase on TCP Throughput --- p.85<br>Chapter 3.5.3 --- A-TCP with Opportunistic Retransmission --- p.86<br>Chapter 3.6 --- Summary --- p.87<br>Chapter 4 --- p.89<br>Impact on Mobile Network Capacity --- p.89<br>Chapter 4.1 --- Introduction --- p.89<br>Chapter 4.2 --- Background and Related Work --- p.91<br>Chapter 4.2.1 --- TCP Performance over Mobile Data Networks --- p.91<br>Chapter 4.2.2 --- Modeling of Mobile Data Networks --- p.92<br>Chapter 4.3 --- System Model --- p.94<br>Chapter 4.3.1 --- Mobile Cell Bandwidth Allocation --- p.95<br>Chapter 4.3.2 --- Markov Chain Model --- p.96<br>Chapter 4.3.3 --- Performance Metric for Mobile Internet --- p.98<br>Chapter 4.3.4 --- Protocol-limited Capacity Loss --- p.100<br>Chapter 4.3.5 --- Channel-limited Capacity Loss --- p.101<br>Chapter 4.4 --- Performance Evaluation --- p.102<br>Chapter 4.4.1 --- Service Response Time --- p.103<br>Chapter 4.4.2 --- Network Capacity Loss --- p.105<br>Chapter 5 --- p.114<br>Mobile Link Queue Length Estimation --- p.114<br>Chapter 5.1 --- Introduction --- p.115<br>Chapter 5.2 --- Sum-of-Delay (SoD) algorithm Revisited --- p.117<br>Chapter 5.2.1 --- Queue Length and Link Buffer Size Estimation --- p.117<br>Chapter 5.2.2 --- A Bound on Estimation Error --- p.120<br>Chapter 5.2.3 --- Impact of Uplink Delay Variations --- p.122<br>Chapter 5.3 --- Uplink Delay Variation Compensation --- p.127<br>Chapter 5.3.1 --- Exploiting the TCP Timestamp Option --- p.127<br>Chapter 5.3.2 --- TCP Timestamp Granularity --- p.130<br>Chapter 5.4 --- Performance Evaluation --- p.131<br>Chapter 5.4.1 --- Link buffer size estimation under uplink delay variations --- p.132<br>Chapter 5.4.2 --- Queue length estimation under uplink delay variations --- p.136<br>Chapter 5.5 --- Summary --- p.136<br>Chapter 6 --- p.139<br>Summary and Future Works --- p.139<br>Chapter 6.1 --- Transparent Protocol Optimization --- p.139<br>Chapter 6.2 --- Cross-Layer Modeling and Optimization of Mobile Networks --- p.141<br>Chapter Appendix A. --- Derivation of Equations (2.24) and (2.25) --- p.143<br>Chapter Appendix B. --- Proof of Theorem 2.1 --- p.145<br>Chapter Appendix C. --- for Proof of Theorem 2.2 --- p.147<br>Chapter Appendix D. --- for Proof of Theorem 2.3 --- p.150<br>Chapter Appendix E. --- for Proof of Theorem 2.4 --- p.151<br>Chapter Appendix F. --- for Proof of Theorem 2.5 --- p.152<br>Chapter Appendix G. --- for Proof of Theorem 2.6 --- p.153<br>Chapter Appendix H. --- for Proof of Theorem 2.7 --- p.156<br>Chapter Appendix I. --- for Proof of Theorem 2.8 --- p.157<br>Chapter Appendix J. --- for Proof of Theorem 3.2 --- p.161<br>Chapter Appendix K. --- for Theorem 3.4 --- p.163<br>Chapter Appendix H. --- for Theorem 3.5 --- p.164<br>Bibliography --- p.166
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Chang, Bo-Hsiu, and 張博修. "Analysis of Packet Signal with TCP Protocol and Network Simulator in Wireless Communication." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/46864241470734109978.
Full textAbstract:
碩士<br>中原大學<br>電機工程研究所<br>92<br>This thesis investigates the problem of analysis of package signal with TCP (Transport Control Protocol) protocol and <a href="http://www.ntsearch.com/search.php?q=network&v=56">network</a> simulator for <a href="http://www.ntsearch.com/search.php?q=wireless&v=56">wireless</a> communication. Via analyzing properties of <a href="http://www.ntsearch.com/search.php?q=wireless&v=56">wireless</a> packages and modifying the existent TCP protocol, an attempt to improve the efficiency of package transaction is proposed by the authors. The simulation results based on NS-2 (Network Simulator version 2) tells us that the designed goals can be reached by this proposal.
There are three steps in our proposal. At first, the difference between wired and <a href="http://www.ntsearch.com/search.php?q=wireless&v=56">wireless</a> packet transaction is analyzed. The basic concept we obtain is that when packet delayed occurs, the control stratagem used in wired transmission is not suitable for the case of <a href="http://www.ntsearch.com/search.php?q=wireless&v=56">wireless</a> transmission. Hence, another difference stratagem for <a href="http://www.ntsearch.com/search.php?q=wireless&v=56">wireless</a> communication is proposed. Then, based on the result of the first step, the TCP protocol of wired transmission will be modified to adapt the case of <a href="http://www.ntsearch.com/search.php?q=wireless&v=56">wireless</a> transmission. Finally, the application <a href="http://www.ntsearch.com/search.php?q=software&v=56">software</a> named “Network Simulator” is used to simulate the new scheme our proposal. The result shows that the modified scheme from wired TCP can perform well in the packet transmission of <a href="http://www.ntsearch.com/search.php?q=wireless&v=56">wireless</a> communication.
There are two significant contributions to the study of how to improve TCP performance in the <a href="http://www.ntsearch.com/search.php?q=wireless&v=56">wireless</a> communication in our proposal as follows：
(1) In the <a href="http://www.ntsearch.com/search.php?q=wireless&v=56">wireless</a> <a href="http://www.ntsearch.com/search.php?q=network&v=56">network</a>, when the transmission quality of signals , by cutting the package into smaller size appropriate, it can really increase the successful probability of transmission.
(2) By applying the technique of to distinguish the case of <a href="http://www.ntsearch.com/search.php?q=network&v=56">network</a> congestion or <a href="http://www.ntsearch.com/search.php?q=network&v=56">network</a> disconnection the working efficiency of traditional TCP can be enhance in our proposal.
The simulation results show that our proposed mechanisms achieve better performance than the existent wired protocol. It is believed that the results of our study in this thesis will be probably practical and efficient on applications of the TCP.
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"SACK TCPVENO: an enhanced version of SACK TCP." 2001. http://library.cuhk.edu.hk/record=b5890850.
Full textAbstract:
by Chung Ling Chi.<br>Thesis (M.Phil.)--Chinese University of Hong Kong, 2001.<br>Includes bibliographical references (leaves 74-76).<br>Abstracts in English and Chinese.<br>Chapter Chapter 1 --- Introduction --- p.1<br>Chapter 1.1 --- Overview --- p.1<br>Chapter 1.2 --- Motivation and Proposed Solution --- p.2<br>Chapter 1.3 --- Organization of the Thesis --- p.4<br>Chapter Chapter 2 --- Background --- p.5<br>Chapter 2.1 --- Basics of Transmission Control Protocol --- p.5<br>Chapter 2.1.1 --- Slow Start and Congestion Avoidance --- p.5<br>Chapter 2.1.2 --- Fast Retransmit and Fast Recovery --- p.7<br>Chapter 2.2 --- SACK TCP Mechanism --- p.8<br>Chapter 2.2.1 --- SACK-permitted Option during Three-way Handshake --- p.8<br>Chapter 2.2.2 --- SACK blocks in SACK Option --- p.9<br>Chapter 2.2.3 --- Interpreting the SACK Option using Scoreboard --- p.10<br>Chapter 2.2.4 --- Retransmission Strategy --- p.11<br>Chapter 2.3 --- TCP Veno Mechanism --- p.13<br>Chapter 2.3.1 --- Refined Additive Increase --- p.13<br>Chapter 2.3.2 --- Refined Multiplicative Decrease --- p.14<br>Chapter Chapter 3 --- SACK TCPVeno --- p.16<br>Chapter 3.1 --- Distinguishing between Types of Packet Loss --- p.17<br>Chapter 3.2 --- Refined Multiplicative Decrease --- p.21<br>Chapter 3.2.1 --- Algorithm --- p.21<br>Chapter 3.2.2 --- Recovery in Consecutive packet Losses --- p.22<br>Chapter 3.2.3 --- Recovering Multiple Packet Losses within a Single Window --- p.26<br>Chapter 3.3 --- Refined Additive Increase --- p.37<br>Chapter 3.3.1 --- Algorithm --- p.37<br>Chapter 3.3.2 --- Advantages --- p.40<br>Chapter 3.4 --- Other Issues --- p.43<br>Chapter 3.4.1 --- Two Side Modifications --- p.43<br>Chapter Chapter 4 --- Experiments --- p.44<br>Chapter 4.1 --- The Network Scenario --- p.44<br>Chapter 4.1.1 --- Dummynet --- p.45<br>Chapter 4.2 --- Experiment Results --- p.47<br>Chapter 4.2.1 --- Single Connection --- p.47<br>Chapter 4.2.1.1 --- Congestion Window Evolution --- p.47<br>Chapter 4.2.1.2 --- Sending Rate and Throughput Evolution --- p.49<br>Chapter 4.2.1.2.1 --- Impact of Packet Loss Rate Due to Lossy Link --- p.49<br>Chapter 4.2.1.2.2 --- Impact of Buffering --- p.52<br>Chapter 4.2.1.2.3 --- Impact of Propagation Delay --- p.57<br>Chapter 4.2.2 --- Multiple Connections --- p.62<br>Chapter 4.2.2.1 --- Fairness --- p.62<br>Chapter 4.2.2.2 --- Compatibility --- p.67<br>Chapter Chapter 5 --- Conclusion --- p.72<br>Bibliography --- p.74
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Rambim, Dorothy Apondi. "Transmission control protocol (TCP) and medium access control (MAC) cross-layer enchancement in wireless." Thesis, 2011. http://encore.tut.ac.za/iii/cpro/DigitalItemViewPage.external?sp=1000384.
Full textAbstract:
M. Tech. Electrical Engineering.<br>Widespread deployment of wireless local area networks (WLANs) and a gradual increase in streaming applications have brought about a demand for improved Quality of Service (QoS) in wireless networks. The IEEE 802.11e standard was proposed to provide QoS mechanisms for assigning high priority to delay-sensitive applications. However, Internet traffic is still dominated by TCP based applications, and the negative effects of the IEEE 802.11e service differentiation scheme on TCP performance in the presence of high priority traffic are becoming a challenging issue. TCP has been found to perform poorly in wireless networks, including IEEE 802.11e; more applications with higher QoS demands use UDP in the transport layer than TCP. Therefore, the QoS of low priority traffic in 802.11e is not guaranteed in networks highly loaded with high priority traffic. This is aggravated by the class differentiation introduced in current QoS protocols, which results in TCP applications being starved during high traffic load. The motivation of this work is to enhance the interaction between the TCP and MAC protocols in order to improve TCP performance in WLANs.