Congestion control mechanism for multimedia applications

  • Cédric Rosman

    Thèse de l'étudiant: Master typesMaster en sciences informatiques

    Résumé

    While TCP and its congestion control mechanism deals with the major share of the Internet traffic today, insuring stability and fairness for users, recently proposed real-time multimedia services (such as IP-telephony, group communication ( video or phone conference), distant learning, ... ) based on the UDP protocol arise. Offering neither reliability nor congestion control mechanism, deploying uncontrolled UDP traffic in a large scale might result in extreme unfairness towards competing TCP traffic. In this thesis, we will compare the two main used transport protocols (TCP and UDP), pointing out the advantages and drawbacks of each related with those new types of services. We will present a new scheme called Rate Adaptive protocol (RAP) for adapting the transmission rate of multimedia applications to the congestion level of the network. RAP was designed to mimic TCP in its behaviour, working in a TCP-Friendly way to avoid starving competing TCP flows. Relying on packets acknowledgment and feedback information, RAP estimates what should be the fair throughput and adapts the time between the sending of two consecutive packets in consequence. Afterwards, we will introduce other congestion control mechanisms, different in their ways of working and implementation, to be compared to RAP. Finally, simulations and measurements of the RAP algorithm will show its TCP-Friendliness related with its consumption of the network resources while competing with multiple TCP flows
    la date de réponse2001
    langue originaleAnglais
    SuperviseurOlivier Bonaventure (Promoteur)

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