On the performance of TCP Vegas over UMTS/WCDMA channels with large round-trip time variations

Anthony Lo, Geert Heijenk

    Research output: Chapter in Book/Report/Conference proceedingConference contributionAcademicpeer-review

    2 Citations (Scopus)
    15 Downloads (Pure)


    Universal Mobile Telecommunications System (UMTS) is a third-generation cellular network that enables high-speed mobile Internet access. This paper evaluates and compares the performance of two well-known versions of Transmission Control Protocol (TCP), namely, Vegas and Reno, in a UMTS environment. Bulk data transfer was considered in the simulation with varying radio channel conditions. We assume that data losses are only due to the radio channel. Simulation results show that the performance of Vegas is worse than Reno even though data losses incurred by the radio channel are completely recovered by the UMTS radio link control layer. This has led us to conduct a thorough investigation on the behavior of Vegas in order to identify the cause of performance degradation in Vegas. The poor performance of Vegas is attributed to the UMTS radio interface characteristics which resulted in large and highly variable TCP round-trip times. Vegas would interpret the round-trip time variation as a sign of congestion, and consequently, shrink its window size which reduces the transmission rate. Furthermore, a sudden increase in the instantaneous round-trip time can trigger spurious timeouts at the TCP sender using Vegas which performs unnecessary retransmissions. Spurious timeouts can lead to significant throughput reduction. Reno, on the other hand, does not show any abnormality and delivers the expected performance.
    Original languageUndefined
    Title of host publicationProceedings IFIP TC6 9th International Conference on Personal Wireless Communications, PWC 2004
    EditorsI.G.M.M. Niemegeers, I.G.M.M. prof.dr.ir. Niemegeers, S.M. Heemstra de Groot, S.M. Dr.ir. Heemstra de Groot
    Place of PublicationBerlin
    Number of pages13
    ISBN (Print)3-540-23162-5
    Publication statusPublished - 2004
    EventPWC 2004: Proceedings of the 9th Int. Conf. on Personal Wireless Communications 2004 - Berlin
    Duration: 21 Sep 200423 Sep 2004

    Publication series

    NameLecture Notes in Computer Science
    ISSN (Print)0302-9743
    ISSN (Electronic)1611-3349


    ConferencePWC 2004


    • METIS-219900
    • EWI-2850
    • IR-62891

    Cite this