Thesis (Ph. D.)--University of Washington, 2005. / Vita. Includes bibliographical references (p. 132-136).

Thesis (M.S.)--Ohio University, March, 2004. / Title from PDF t.p. Includes bibliographical references (p. 58-61)

Thesis (Ph.D.) - University of Queensland, 2005. / Includes bibliography.

Techn. University, Diss., 2003--Darmstadt.

Το VoIP (Voice Over IP) αναφέρεται στη μετάδοση και τη σηματοδοσία επικοινωνιών φωνής π.χ τηλεφωνικές κλήσεις πάνω από IP δίκτυα όπως είναι το διαδίκτυο. Σκοπός της παρούσας διπλωματικής ήταν η μελέτη της παρεχόμενης ποιότητας ομιλίας VoIP τηλεφωνικών συσκευών (Sitel,Polycom) κάτω από σενάρια διαφορετικών συνθηκών κίνησης στο δίκτυο. Αρχικά παρουσιάζονται οι εφαρμογές του voip και στη συνέχεια αναλύονται η λειτουργία, η αρχιτεκτονική και τα πρωτόκολλα της τεχνολογίας αυτής. Ακολούθως περιγράφεται η πειραματική διάταξη που απαιτήθηκε για να συγκεντρωθούν οι μετρήσεις από τις συσκευές και στη συνέχεια οι γραφικές αναπαραστάσεις των μετρήσεων αυτών που αφορούν της παρεχόμενη ποιότητα ομιλίας. Γίνεται ανάλυση των γραφικών και σύγκριση με ανάλογες της βιβλιογραφίας. / The VoIP technology refers to the transmission of voice samples over the Internet Protocol. The aim of the thesis is to investigate the QoS of a VoIP call under various networks circumstances when various impairments occur. The devices that we put under test belong to Sitel and Polycom company.

Thesis (MScEng) -- Stellenbosch University, 2004. / ENGLISH ABSTRACT: Interest in TCP/IP as a communication protocol for use in space communication has increased substantially with the growth of the world wide web (WWW). TCP/IP is a relevant communication protocol for space based communication systems that need to access the broader terrestrial communication network. Low Earth Orbit(LEO) satellites have very short delay times between themselves and the ground, and correspondingly very short connection times. Staying in contact with a LEO satellite continuously through a space-based network requires large constellations of satellites and complex routing strategies. Connectivity with the world wide web using a widely accepted protocol such as TCP/IP is desirable because it would make communication with the satellite over a terrestrial station possible, were it to route communication onto the WWW. This thesis looks at the expected TCP/IP performance over satellite network links, identifies problem areas for current TCP/IP technologies, and makes suggestions for optimizing TCP/IP over such links. The thesis also introduces a new performance benchmark, the equivalence level, allowing for the simplified description of TCP throughput behaviour over a broad range of network parameters. The performance of the Linux kernel release 2.4.18 TCP/IP stack is also evaluated. / AFRIKAANSE OPSOMMING: Die belangstelling in TCP/IP as ’n kommunikasie protokol vir gebruik in die ruimte het kenmerklik toegeneem met die groei van die wereld wye web (WWW). TCP/IP is ’n relevante protokol vir kommunikasie stelsels in die ruimte, veral met die doel om toegang tot land gebaseerde kommunikasie netwerke te kry. Lae wentelbaan sateliete het baie kort vertragingstye tussen die aarde en die sateliet, en gevolglik baie kort verbindingstye. Groot sateliet konstelasies en komplekse verbintenis strategie word benodig om ’n lae wentelbaan sateliet deurentyd in kontak te hou met ’n ruimtegebaseerde netwerk. Verbinding met die wereld wye web deur die gebruik van ’n wyd aanvaarde protokol, soos TCP/IP, is wenslik, want dit sal kommunikasie met die sateliet oor ’n aardgebaseerde stasie moontlik maak, sou dit kommunikasie oor die wereld wye web stuur. Hierdie tesis kyk na die verwagte werking van TCP/IP oor sateliet netwerk konneksies, identifiseer probleme met huidiglike TCP/IP tegnologie, en maak voorstellings vir die optimale funtionering van TCP/IP oor sulke konneksies. Hierdie tesis stel ook ’n nuwe werkverrigtings maatstaf, die gelykheidsvlak, wat die vereenvoudige beskrywing van TCP/IP data tempo gedrag oor ’n groot variasie van netwerk parameters toelaat. Die werking van die Linux Kernel 2.4.18 TCP/IP stapel word ook geevalueer.

This study investigates Audio over IP. A stress test was used to see what impact asymmetric latency had on the audio signal in a closed network. The study was constructed into two parts. The first part is the stress test where two AoIP solutions were tested. The two solutions where exposed in two forms of asymmetric latency. First a fixed value was used, next, a custom script was used to simulate changing values of asymmetric latency. The second part of this study involved interviews that where conducted with representatives from the audio industry that are working with audio over IP on a dayto-day usage. The goal for these interviews was to figure out what knowledge the audio industry had about asymmetric latency, if the industry had experienced problems related to latency and what general knowledge the industry has about networks. It was found in the interviews that the limitation in AoIP isn’t the technology in itself but rather missing knowledge with the people that are using the systems.

Internet applications make use of the services provided by a transport protocol, such as TCP (a reliable, in-order stream protocol). We use this term Transport Service to mean the end-to- end service provided to application by the transport layer.   That service can only be provided correctly if information about the intended usage is supplied from the application. The application may determine this information at the design time, compile time, or run time, and it may include guidance on whether a feature is required, a preference by the application, or something in between. Multipath TCP (MPTCP) adds the capability of using multiple paths to a regular TCP session. Even though it is designed to be totally backward compatible to applications. The data transport differs compared to regular TCP, and there are several additional degrees of freedom that the particular application may want to exploit.   Multipath TCP is particularly useful in the context of wireless networks using both Wi-Fi and a mobile network is a typical use case. In addition to the gains in throughput from inverse multiplexing, links may be added or dropped as the user moves in or out of coverage without disrupting the end-to-end TCP connection. The problem of link handover is thus solved by abstraction in the transport layer, without any special mechanisms at the network or link level.   Handover functionality can then be implemented at the endpoints without requiring special functionality in the sub-networks according to the Internet's end-to-end principle. Multipath TCP can balance a single TCP connection across multiple interfaces and reach very high throughput.

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico, Programa de Pós-Graduação em Ciência da Computação, Florianópolis, 2001. / Made available in DSpace on 2012-10-18T04:35:40Z (GMT). No. of bitstreams: 1 273419.pdf: 943803 bytes, checksum: 63cb467e5261bff804b15d6d9d268044 (MD5) / A finalidade deste trabalho é apresentar um modelo de aplicativo capaz de trafegar dados de e para dispositivos seriais através de uma infra-estrutura de rede baseada nos protocolos TCP/IP, e mais especificamente no protocolo de rede IPv4 e de transporte TCP. Tal capacidade é normalmente conhecida como tunelamento. Os dados seriais a serem enviados podem ser representados de diferentes formas, escolhida quando de sua utilização, podendo ser essencialmente dados seriais no padrão RS-232, assim como estruturas de dados mais complexas, que serão traduzidas no aplicativo para dados seriais puros, que serão por sua vez enviados ao dispositivo serial. O aplicativo é composto de um módulo de gerência, o qual compõe o servidor, e um módulo de tunelamento responsável pelo tráfego dos dados. Para validar a proposta foram desenvolvidos dois aplicativos separados, um para cada módulo.

Monitoring unused IP address space by using network telescopes provides a favourable environment for researchers to study and detect malware, worms, denial of service and scanning activities. Research in the field of network telescopes has progressed over the past decade resulting in the development of an increased number of overlapping datasets. Rhodes University's network of telescope sensors has continued to grow with additional network telescopes being brought online. At the time of writing, Rhodes University has a distributed network of five relatively small /24 network telescopes. With five network telescope sensors, this research focuses on comparative and correlation analysis of traffic activity across the network of telescope sensors. To aid summarisation and visualisation techniques, time series' representing time-based traffic activity, are constructed. By employing an iterative experimental process of captured traffic, two natural categories of the five network telescopes are presented. Using the cross- and auto-correlation methods of time series analysis, moderate correlation of traffic activity was achieved between telescope sensors in each category. Weak to moderate correlation was calculated when comparing category A and category B network telescopes' datasets. Results were significantly improved by studying TCP traffic separately. Moderate to strong correlation coefficients in each category were calculated when using TCP traffic only. UDP traffic analysis showed weaker correlation between sensors, however the uniformity of ICMP traffic showed correlation of traffic activity across all sensors. The results confirmed the visual observation of traffic relativity in telescope sensors within the same category and quantitatively analysed the correlation of network telescopes' traffic activity.