Please use this identifier to cite or link to this item: http://scholarbank.nus.edu.sg/handle/10635/134408
Title: DETECTION AND ALLEVIATION OF LAST-MILE WIRELESS LINK BOTTLENECKS
Authors: NIMANTHA THUSHAN BARANASURIYA
Keywords: Last-Mile,Wireless,Bottleneck,Detection,Alleviation
Issue Date: 15-Jul-2016
Source: NIMANTHA THUSHAN BARANASURIYA (2016-07-15). DETECTION AND ALLEVIATION OF LAST-MILE WIRELESS LINK BOTTLENECKS. ScholarBank@NUS Repository.
Abstract: Increasingly, a significant portion of users connect to the Internet via wireless connections, i.e., cellular or Wi-Fi. This phenomenon can be attributed to the proliferation of hand-held devices. With the advent of these devices, network service providers have to increase the performance of the last-mile connection so that users have uninterrupted, high-bandwidth access to the Internet. In this thesis, we first show the impact of the last-mile connection on the user- perceived quality of end-to-end network connections by conducting large-scale measurement studies. Specifically, we consider two last-mile technologies: cellular (3G and LTE) and Wi-Fi, and quantify their effect on real-time data streams such as VoIP calls. These measurement studies show that last-mile wireless links can often be the bottleneck link in a given path, but the existence of WAN path bottlenecks is substantial as well. Therefore, it is of great importance to identify where network bottlenecks lie in order to take the appropriate remedial actions. In this regard, first, we present QProbe, a lightweight tool that provides diagnostic information about a user’s cellular link. QProbe identifies whether an end-to- end network path is bottlenecked by the cellular link or the Internet path with > 85% accuracy. Next, we present a suite of techniques named Kwikr that Wi-Fi connected clients can use to detect various forms of pathology conditions that might be present in their Wi-Fi connections, with > 90% accuracy. Real-time streaming is an important class of applications that is used by millions of people all over the world. Despite their importance, our measurement studies show that quite often Wi-Fi last-mile connections cause quality degradations in real-time streams. To address such issues, in the latter part of this thesis, we present two systems that make real-time streaming reliable and robust on Wi-Fi last-mile links by alleviating bottleneck conditions that occur on them. First, we show how we can alleviate Wi-Fi bottlenecks in real-time streaming applications by allowing them to perform “Wi-Fi-aware” bandwidth adaptation using a novel system named KwikrAdapt. Next, we present another Wi-Fi bottleneck alleviation system, named DiversiFi, that improves the quality of real-time streams by performing cross-link packet replication across multiple Wi-Fi links, while ensuring the overhead of doing so is kept low. Both these systems significantly improves the quality of real-time streams and makes them robust.
URI: http://scholarbank.nus.edu.sg/handle/10635/134408
Appears in Collections:Ph.D Theses (Open)

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