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  • PhD Defense - Kyriakos Zarifis

    Wed, May 09, 2018 @ 01:00 PM - 03:00 PM

    Computer Science

    University Calendar

    Title: Making Web Transfers More Efficient

    PhD Candidate: Kyriakos Zarifis

    Date: 05-09-18
    SAL 322

    Ethan Katz-Bassett (Chair)
    Ramesh Govindan
    Konstantinos Psounis (Outside)

    Delays in web applications have been repeatedly shown to negatively impact business revenues. In this dissertation we perform studies related to Web transfer delays specific to propagation delay due to inflated paths, and delays in transferring data between servers and clients due to inefficient use of the communication channels.
    Previous research has shown that the shortest path between a client and a server is not always selected, due to routing protocol policy-based decisions. We develop a methodology identify root causes of path inflation, specifically focusing on mobile traffic directed to Google servers, in order to understand the evolution of the infrastructure of mobile carrier networks and how it can affect user experience.
    Once a connection has been established, information is exchanged between the two hosts according to rules defined by HTTP, the application layer protocol used for today's Web transfers. In this work we develop a model of the new version of HTTP/2 and pass through it a large dataset of HTTP/1 traces, in order to understand the performance implications of deploying the new version of the protocol in the wild. Our study exposes several opportunities for improvements, specifically using a new feature that allows a server to send to the client an object without the client requesting it. Generalizing from that observation, we design, develop and evaluate a system that allows CDNs to utilize idle network time around page downloads to send to the client content that the client is expected to request in the current or next page navigation. We show that if implemented correctly, speculative content prepositioning on the client can achieve a performance improvement comparable to having a page loaded on the client cache.

    Location: 322

    Audiences: Everyone Is Invited

    Contact: Lizsl De Leon


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