128 research outputs found

    DCCP Simultaneous-Open Technique to Facilitate NAT/Middlebox Traversal

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    https://datatracker.ietf.org/doc/rfc5595/Publisher PD

    Unicast UDP Usage Guidelines for Application Designers

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    Publisher PD

    Study of Middle-box Behavior on Transport Layer Protocols

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    Global connectivity architecture of mobile personal devices

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    Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2008.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Includes bibliographical references (p. 193-207).The Internet's architecture, designed in the days of large, stationary computers tended by technically savvy and accountable administrators, fails to meet the demands of the emerging ubiquitous computing era. Nontechnical users now routinely own multiple personal devices, many of them mobile, and need to share information securely among them using interactive, delay-sensitive applications.Unmanaged Internet Architecture (UIA) is a novel, incrementally deployable network architecture for modern personal devices, which reconsiders three architectural cornerstones: naming, routing, and transport. UIA augments the Internet's global name system with a personal name system, enabling users to build personal administrative groups easily and intuitively, to establish secure bindings between his devices and with other users' devices, and to name his devices and his friends much like using a cell phone's address book. To connect personal devices reliably, even while mobile, behind NATs or firewalls, or connected via isolated ad hoc networks, UIA gives each device a persistent, location-independent identity, and builds an overlay routing service atop IP to resolve and route among these identities. Finally, to support today's interactive applications built using concurrent transactions and delay-sensitive media streams, UIA introduces a new structured stream transport abstraction, which solves the efficiency and responsiveness problems of TCP streams and the functionality limitations of UDP datagrams. Preliminary protocol designs and implementations demonstrate UIA's features and benefits. A personal naming prototype supports easy and portable group management, allowing use of personal names alongside global names in unmodified Internet applications. A prototype overlay router leverages the naming layer's social network to provide efficient ad hoc connectivity in restricted but important common-case scenarios.(cont) Simulations of more general routing protocols--one inspired by distributed hash tables, one based on recent compact routing theory--explore promising generalizations to UIA's overlay routing. A library-based prototype of UIA's structured stream transport enables incremental deployment in either OS infrastructure or applications, and demonstrates the responsiveness benefits of the new transport abstraction via dynamic prioritization of interactive web downloads. Finally, an exposition and experimental evaluation of NAT traversal techniques provides insight into routing optimizations useful in UIA and elsewhere.by Bryan Alexander Ford.Ph.D

    An Experimental Study of Home Gateway Characteristics

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    Many residential and small business users connect to the Internet via home gateways, such as DSL and cable modems. The characteristics of these devices heavily influence the quality and performance of the Internet service that these users receive. Anecdotal evidence suggests that an extremely diverse set of behaviors exists in the deployed base, forcing application developers to design for the lowest common denominator. This paper experimentally analyzes some characteristics of a substantial number of different home gateways: binding timeouts, queuing delays, throughput, protocol support and others.Peer reviewe

    Unicast UDP Usage Guidelines for Application Designers

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    Xarxa mesh privada virtual

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    Aquest projecte ens apropa als conceptes com les xarxes privades virtuals, els serveis de seguretat (xifrar el tràfic, validar la integritat, autentificar els extrems, evitar el repudi i evitar la repetició) i les aplicacions distribuïdes (peer to peer). Avui en dia, la funció de permetre la unió de diferents ordenadors o xarxes locals en una nova xarxa virtual, pot ser aprofitada per poder abstraure’s de les barreres imposades per IPv4 com la limitació d’adreçament públic. El fet d’afegir la component de privacitat permet forçar un entorn segur, de confiança i independent del que puguin aportar les aplicacions. El conjunt de la creació de xarxes virtuals amb la component de privacitat permet la creació de xarxes privades virtuals també anomenades VPNs. L’objectiu d’aquest projecte és dissenyar i implementar una aplicació capaç de crear xarxes privades virtuals que no depenguin de cap servidor central, sense que això comprometi la privacitat ni l’autenticació dels integrants de la xarxa. L’aplicació ha de ser capaç de superar els Routers NAT (que tradueixen les adreces IP permetent compartir una adreça pública entre diferents ordenadors) per tal d’establir connexions bidireccionals directament amb els veïns de la xarxa virtual, proporcionant així una baixa latència. En fer els tests inicials es va trobar un problema relacionat amb la implementació de la llibreria OpenSSL del protocol segur utilitzat. Aquest error es presenta malgrat que aparentment l’aplicació fa un bon ús d’aquesta llibreria. Aquest problema ha consumit molt temps de dedicació del projecte sense poder ser solucionat. Com a resultats dels tests de l’aplicació creada en comparació amb les de les altres aplicacions existents: aquesta realitza una inicialització breu, te una latència baixa juntament amb una desviació estàndard molt baixa i permet taxes de transferència altes en TCP i baixes en UDP. Aquest document comença amb una introducció a les xarxes privades virtuals i al projecte.Seguidament, en el primer capítol s’exposa la descripció i la comparativa de les tecnologies de xarxes privades virtuals existents. En el segon s’explica el funcionament, el disseny i l’arquitectura de l’aplicació creada. En el tercer es presenten els resultats de les proves realitzades amb l’aplicació creada. I finalment hi ha les conclusions, la bibliografia i el glossari

    Design, Implementation, and Performance Analysis of In-Home Video based Monitoring System for Patients with Dementia

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    Dementia is a major public health problem affecting 35 million people in USA. The caregivers of dementia patients experience many types of physical and psychological stress while dealing with disruptive behaviors of dementia patients. This will also result in frequent hospitalizations and re-admissions. In this project we design, implement, and measure the performance of an advanced video based monitoring system to aide the caregivers in managing the behavioral symptoms of dementia patients. The caregivers will be able to easily capture and share the antecedents, consequences, and the function of behavior, through a video clip, and get the real-time feedback from clinical experts. Overall the system will help in reducing the hospital admission/readmission, improve the quality of life for caregivers, and in general result in reduced cost of health care systems. System is developed using python scripts, open source web frameworks, FFmpeg tool chain, and commercial off-the-shelf IP camera and mini-PC. WebRTC is used for video based coaching of caregivers. A framework has been developed to evaluate the storage and retrieval latency of video clips to public and On-premise clouds, video streaming performance in LAN and WLAN environments, and WebRTC performance in different types of access networks. InstaGENIrack, a GENI rack in KU is used as on-premise cloud infrastructure for the evaluation. OpenSSL utilities are employed for secured transport and storage of captured video clips. We conducted the trials in Google fiber ISP in Kansas city, and compared the performance with other traditional ISPs
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