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Aspects of Quality: Using Quality Measurements to Improve Computer Network Performance
KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Network Systems Laboratory (NS Lab).ORCID iD: 0000-0002-1737-133X
2016 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

As computer networks grow in complexity, measuring the performance becomes a challenge. Intrinsic properties of the networks capability to transport data, such as bandwidth, latency, loss, and error rate are not always enough to provide a clear picture of how well the network can satisfy the users' expectations. In these situations, the relationship between the users' expectations and the quality provided by the network is of interest. Today multiple approaches to quantifying quality exists, such as Quality of Service (QoS), Quality of Experience (QoE) and Quality of Information (QoI). In this thesis, we explore how such quality measurements can be used as means to improve network performance. In the first part, we examine the Quality of Service in shared experiment networks, with a focus on the FEDERICA network. We present a method for statistical analysis of metadata, based on clustering. We show that, using this method, it is possible to improve the reliability of experiments in shared experiment networks. In the second part, we take a Quality of Experience viewpoint, while doing experimental development. The goal is to improve the mobility performance of an implementation of the Stream Control Transfer Protocol (SCTP) on mobile devices. We present optimisations of the SCTP implementation along with a mobility framework, which simplifies the introduction of mobility functionality in an existing SCTP application. We show that by using this combination, it is possible to perform seamless vertical handover between WiFi and 3G cellular networks. In the third part, we focus on Quality of Information in Delay Tolerant Wireless Sensor Networks (DT-WSN). We study how it is possible to improve the quality of the measurements obtained under conditions where bandwidth and storage capacity are limited, forcing the network to discard a significant fraction of the data. We introduce the SmartGap algorithm, a buffer management algorithm for DT-WSNs, and demonstrate that this algorithm can provide significantly improved QoI over a wide range of network configurations.

Abstract [sv]

De datornätverk som vi bygger idag är så komplexa att det kan vara svårt att mäta hur de presterar. Vi kan mäta grundläggande egenskaper, såsom bandbredd, genomströmning, latens, paketspridning och förluster, men det går inte alltid att direkt översätta resultatet av våra mätningar i en användarupplevelse. I det läget är förhållandet mellan användarens förväntningar och den kvalité som nätverket levererar intressant. Det har utvecklats en mängd olika lösningar för att mäta kvalité, så som tjänstekvalité (Quality of Service, QoS), upplevelsekvalité (Quality of Experience, QoE) och informationskvalité (Quality of Information, QoI). I detta arbete undersöker vi prestandan i komplexa nätverk, för att sedan försöka förbättra den. Vi grundar vårt arbete på mätningar av den nuvarande prestandan som vi kombinerar med relevanta kvalitetsaspekter. Arbetet görs i tre delar, i tre olika typer av nätverk. Vi fokuserar på olika kvalitétsmått i de olika delarna.I första delen så studerar vi tjänstekvalité (QoS) i delade forskningsnätverk, och då framförallt FEDERICA. Vi undersöker hur vi kan samla olika typer av information om nätverket och använda detta som en form av metadata om nätverket. Sedan presenterar vi en metod där vi använder statistisk analys och gruppering av metadata för att kunna dra slutsatser om nätverkets egenskaper. Vi visar att metoden kan förbättra tillförlitligheten hos experiment som utförs i delade forskningsnätverk.I andra delen fokuserar vi på upplevelsekvalité (QoE) och använder en experimentbaserad metod för att utveckla ett protokoll. Vi arbetar med övergångar mellan WiFI och mobila nätverk (så kallade vertikala övergångar) när vi använder SCTP-protokollet. Vid vertikala övergångar byter en enhet till ett nytt anslutningsmedium (från WiFi till mobilt nätverk eller tvärt om) men behåller de kommunikationsvägar som har etablerats. Målet är att användaren inte skall uppleva en kvalitésänkning när en övergång sker, vilket gör övergången transparent. Vi använder en kombination av vanliga mobiltelefoner och produktionsnätverk. Under arbetets gång utför vi experiment och samlar data om hur näten fungerar. Vi använder sedan den information för att identifiera olika faktorer som påverkar våra resultat. För att förbättra prestandan, och underlätta utvecklingen, introducerar vi ett ramverk för vertikala övergångar. Ramverket kombineras sedan med väl valda inställningar och en policy för vertikala övergångar baserat på signalstyrkan hos de anslutningspunkter som enheten har. Med den kombinationen visar vi att det är möjligt att genomföra transparenta övergångar.I tredje delen av arbetet utgår vi från informationskvalité (QoI) när vi undersöker störningståliga trådlösa sensornätverk (Delay/Distruption Tolerant Wireless Sensor Networks, DT-WSN). Vi undersöker hur vi kan förbättra kvalitén på mätningar i situationer där bandbredd och lagringskapacitet är kraftigt begränsaded, vilket gör att nätverket måste slänga bort en stor del av den insamlade datan. Som en del av detta arbete introducerar vi SmartGap, en bufferhanteringsalgorithm som fokuserar på informationskvalité för mätningar i DT-WSN. Vi studerar också vilka faktorer som är viktiga vid utvärdering av bufferhanteringsalgoritmer för DT-WSN.

Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2016. , xii, 187 p.
Series
TRITA-ICT-EX, 2016:04
National Category
Telecommunications
Research subject
Computer Science
Identifiers
URN: urn:nbn:se:kth:diva-184499ISBN: 978-91-7595-869-9 (print)OAI: oai:DiVA.org:kth-184499DiVA: diva2:916220
Public defence
2016-04-29, Sal C, Electrum, KTH Skolan för informations- och kommunikationsteknik, Kistagången 16, Kista, 13:00 (English)
Supervisors
Funder
Wireless@kthVINNOVAEU, FP7, Seventh Framework Programme
Available from: 2016-04-06 Created: 2016-04-01 Last updated: 2016-04-06Bibliographically approved
List of papers
1. Enabling future internet research: the FEDERICA case
Open this publication in new window or tab >>Enabling future internet research: the FEDERICA case
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2011 (English)In: IEEE Communications Magazine, ISSN 0163-6804, E-ISSN 1558-1896, Vol. 49, no 7, 54-61 p.Article in journal (Refereed) Published
Abstract [en]

The Internet, undoubtedly, is the most influential technical invention of the 20th century that affects and constantly changes all aspects of our day-to-day lives nowadays. Although it is hard to predict its long-term consequences, the potential future of the Internet definitely relies on future Internet research. Prior to every development and deployment project, an extensive and comprehensive research study must be performed in order to design, model, analyze, and evaluate all impacts of the new initiative on the existing environment. Taking the ever-growing size of the Internet and the increasing complexity of novel Internet-based applications and services into account, the evaluation and validation of new ideas cannot be effectively carried out over local test beds and small experimental networks. The gap which exists between the small-scale pilots in academic and research test beds and the realize validations and actual deployments in production networks can be bridged by using virtual infrastructures. FEDERICA is one of the facilities, based on virtualization capabilities in both network and computing resources, which creates custom-made virtual environments and makes them available for Future Internet Researchers. This article provides a comprehensive overview of the state-of-the-art research projects that have been using the virtual infrastructure slices of FEDERICA in order to validate their research concepts, even when they are disruptive to the test bed’s infrastructure, to obtain results in realistic network environments.

Place, publisher, year, edition, pages
IEEE, 2011
Keyword
FEDERICA;future Internet research;production networks;virtual infrastructures;virtualization capabilities;Internet;virtualisation;
National Category
Telecommunications
Identifiers
urn:nbn:se:kth:diva-59688 (URN)10.1109/MCOM.2011.5936155 (DOI)000292376000006 ()2-s2.0-79959961303 (Scopus ID)
Projects
FEDERICA
Funder
EU, FP7, Seventh Framework Programme
Note

QC 20120119

Available from: 2012-01-19 Created: 2012-01-11 Last updated: 2017-12-08Bibliographically approved
2. Using metadata to improve experiment reliability in shared environments
Open this publication in new window or tab >>Using metadata to improve experiment reliability in shared environments
2012 (English)In: Traffic monitoring and analysis, Springer Berlin/Heidelberg, 2012, Vol. 7189 LNCS, 129-142 p.Conference paper, Published paper (Refereed)
Abstract [en]

Experimental network research is subject to challenges since the experiment outcomes can be influenced by undesired effects from other activities in the network. In shared experiment networks, control over resources is often limited and QoS guarantees might not be available. When the network conditions vary during a series of experiment unwanted artifacts can be introduced in the experimental results, reducing the reliability of the experiments. We propose a novel, systematic, methodology where network conditions are monitored during the experiments and information about the network is collected. This information, known as metadata, is analyzed statistically to identify periods during the experiments when the network conditions have been similar. Data points collected during these periods are valid for comparison. Our hypothesis is that this methodology can make experiments more reliable. We present a proof-of-concept implementation of our method, deployed in the FEDERICA and PlanetLab networks.

Place, publisher, year, edition, pages
Springer Berlin/Heidelberg, 2012
Series
Lecture Notes in Computer Science, ISSN 0302-9743 ; 7189
Keyword
Clustering, FEDERICA, Measuring, Metadata, Planetlab, Data points, Network condition, Proof of concept, QoS guarantee, Quality of service, Reliability analysis, Experiments
National Category
Communication Systems
Identifiers
urn:nbn:se:kth:diva-99774 (URN)10.1007/978-3-642-28534-9_15 (DOI)2-s2.0-84858396467 (Scopus ID)978-364228533-2 (ISBN)
Conference
4th International Workshop on Traffic Monitoring and Analysis, TMA 2012; Vienna;12 March 2012 through 12 March 2012
Funder
ICT - The Next Generation
Note

QC 20120801

Available from: 2012-08-01 Created: 2012-08-01 Last updated: 2016-04-06Bibliographically approved
3. An SCTP-based mobility management framework for smartphones and tablets
Open this publication in new window or tab >>An SCTP-based mobility management framework for smartphones and tablets
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2012 (English)In: Proceedings - 26th IEEE International Conference on Advanced Information Networking and Applications Workshops, WAINA 2012, IEEE Computer Society, 2012, 1107-1112 p.Conference paper, Published paper (Refereed)
Abstract [en]

The current wireless network landscape comprises a plethora of technologies including WLAN, WiMAX and 3G, and not much speaks for a radical change of the state of affairs in the near future. In light of this, it becomes pivotal to facilitate vertical handover between different types of wireless networks. Although, a large number of vertical handover schemes have been proposed in the past several years, the majority of the proposed solutions reside in the network and/or link layer - e.g., Mobile IP and various IEEE 802.21 schemes - and relatively few are transport-layer solutions. However, we think transport-layer solutions many times are attractive, particularly in cases where there are no economic incentives to upgrade the existing network infrastructure. To this end, we have designed a lightweight, transport-level mobility framework based on the Stream Control Transmission Protocol (SCTP) and its extension for dynamic address reconfiguration. The framework API has been kept very small and closely aligned with the SCTP sockets extensions, which makes porting of existing applications fairly straightforward. To demonstrate its usefulness for low-power tablets and smart phones, we have implemented our framework on a Motorola Xoom tablet running the Android OS. Our initial proof-of-concept experiment gave satisfactory results with a handover performance on par with that of other vertical handover solutions.

Place, publisher, year, edition, pages
IEEE Computer Society, 2012
Keyword
Dynamic address reconfiguration, Economic incentive, Handover performance, IEEE802.21, Link layers, Low Power, Mobile iP, Mobility management, Motorola, Network infrastructure, Proof of concept, State of affairs, Stream control transmission protocols, Vertical handovers, Interoperability, Smartphones, Wimax, Wireless networks, Internet protocols
National Category
Telecommunications
Identifiers
urn:nbn:se:kth:diva-100057 (URN)10.1109/WAINA.2012.84 (DOI)2-s2.0-84860709377 (Scopus ID)978-076954652-0 (ISBN)
Conference
26th IEEE International Conference on Advanced Information Networking and Applications Workshops, WAINA 2012; Fukuoka;Japan 26 March 2012 through 29 March 2012
Note

QC 20150708

Available from: 2012-08-03 Created: 2012-08-03 Last updated: 2016-04-06Bibliographically approved
4. Sub-second transport layer vertical handover using mSCTP in Android mobile devices
Open this publication in new window or tab >>Sub-second transport layer vertical handover using mSCTP in Android mobile devices
2012 (English)In: Wireless Communication Systems (ISWCS), 2012 International Symposium on, IEEE , 2012, 661-665 p.Conference paper, Published paper (Refereed)
Abstract [en]

Contemporary mobile devices such as smartphones and tablets are increasingly equipped with multiple network interfaces that enable automatic vertical handover between heterogeneous wireless networks including WiFi and cellular 3G and 4G networks. However, the employed vertical handover schemes are mostly quite simple, and incur non-negligible service disruptions to ongoing sessions, e.g., video streaming and live conferencing sessions. A number of improved mobility management frameworks for these lightweight mobile devices have been proposed in the past recent years. Although these may result in negligible service disruptions, the vast majority of them are network- or integrated network- and link-layer based, and require support in the infrastructure to be successfully deployed. This paper demonstrates the feasibility of using an infrastructure-independent, transport-level vertical handover scheme on a smartphone for an application as demanding as video streaming. In our study, we used a previously developed Android-based mobility framework. The study shows that a standardized mobility solution based on the Stream Control Transmission Protocol (SCTP) and its extension for Dynamic Address Reconfiguration (DAR), incurs a service disruption on par with comparable proposed network- and link-layer solutions.

Place, publisher, year, edition, pages
IEEE, 2012
Series
Proceedings of the International Symposium on Wireless Communication Systems, ISSN 2154-0217
Keyword
4G networks, Dynamic address reconfiguration, Heterogeneous wireless network, Integrated networks, Mobility management, Mobility solutions, Service disruptions, Stream control transmission protocols, Transport layers, Vertical handovers, Communication systems, Heterogeneous networks, Mobile devices, Robots, Smartphones, Video streaming, Mobile telecommunication systems
National Category
Communication Systems
Identifiers
urn:nbn:se:kth:diva-116659 (URN)10.1109/ISWCS.2012.6328450 (DOI)2-s2.0-84871342143 (Scopus ID)978-146730760-4 (ISBN)
Conference
2012 9th International Symposium on Wireless Communication Systems, ISWCS 2012, 28 August 2012 through 31 August 2012, Paris
Note

QC 20130123

Available from: 2013-01-23 Created: 2013-01-22 Last updated: 2016-04-06Bibliographically approved
5. Handover in the Wild: The feasibility of vertical handover in commodity smartphones
Open this publication in new window or tab >>Handover in the Wild: The feasibility of vertical handover in commodity smartphones
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2013 (English)In: Communications (ICC), 2013 IEEE International Conference on, IEEE conference proceedings, 2013, 6401-6406 p.Conference paper, Published paper (Refereed)
Abstract [en]

Today commodity mobile devices are equipped withmultiple wireless access technologies. To enable continuous connectivityit is vital that these terminals provide for vertical handover between different technologies. Particularly, they should provide a vertical handover that complies with the timeliness requirements of soft real-time applications. Considering aspects such as cost- and ease-of-deployment, application neutrality, and, not least, the emergence of transport protocols that support multi-homing such as mobile SCTP and multi-path TCP, we think it would be beneficial to handle vertical handover in thetransport layer of the mobile terminal. This paper demonstrates through several real-world experiments, the feasibility of using a lightweight vertical handover scheme in smart mobile terminals for live video streaming. The vertical handover criteria is basedon the received signal strength. Our experiments suggest that thescheme indeed provides for seamless vertical handover at walking speed – our target scenario. However, the experiments also suggest that the scheme gives significant reductions in handovertime, as compared to mobile SCTP without improvements, at higher speeds.

Place, publisher, year, edition, pages
IEEE conference proceedings, 2013
Series
IEEE International Conference on Communications, ISSN 1550-3607
Keyword
Live video streaming, Real world experiment, Received signal strength, Seamless vertical handover, Soft real-time applications, Transport protocols, Vertical handovers, Wireless access technology
National Category
Communication Systems
Identifiers
urn:nbn:se:kth:diva-122409 (URN)10.1109/ICC.2013.6655635 (DOI)000349673807056 ()2-s2.0-84891348381 (Scopus ID)978-146733122-7 (ISBN)
Conference
2013 IEEE International Conference on Communications, ICC 2013; Budapest; Hungary; 9 June 2013 through 13 June 2013
Funder
VINNOVA
Note

QC 20140205. Updated from manuscript to conference paper

Available from: 2013-05-20 Created: 2013-05-20 Last updated: 2016-04-06Bibliographically approved
6. Mind the SmartGap: A Buffer Management Algorithm For Delay Tolerant Wireless Sensor Networks
Open this publication in new window or tab >>Mind the SmartGap: A Buffer Management Algorithm For Delay Tolerant Wireless Sensor Networks
2015 (English)In: Wireless Sensor Networks: 12th European Conference, EWSN 2015, Porto, Portugal, February 9-11, 2015. Proceedings / [ed] Tarek Abdelzaher, Nuno Pereira, Eduardo Tovar, Springer, 2015, Vol. 8965, 104-119 p.Conference paper, Published paper (Refereed)
Abstract [en]

Limited memory capacity is one of the major constraints in Delay Tolerant Wireless Sensor Networks. Efficient management of the memory is critical to the performance of the network. This paper proposes a novel buffer management algorithm, SmartGap, a Quality of Information (QoI) targeted buffer management algorithm. That is, in a wireless sensor network that continuously measures a parameter which changes over time, such as temperature, the value of a single packet is governed by an estimation of its contribution to the recreation of the original signal. Attractive features of SmartGap include a low computational complexity and a simplified reconstruction of the original signal. An analysis and simulations in which the performance of SmartGap is compared with the performance of several commonly used buffer management algorithms in wireless sensor networks are provided in the paper. The simulations suggest that SmartGap indeed provides significantly improved QoI compared the other evaluated algorithms.

Place, publisher, year, edition, pages
Springer, 2015
National Category
Telecommunications
Research subject
Computer Science
Identifiers
urn:nbn:se:kth:diva-166705 (URN)10.1007/978-3-319-15582-1_7 (DOI)000357677300007 ()978-3-319-15582-1 (ISBN)978-3-319-15581-4 (ISBN)
Conference
12th European Conference on Wireless Sensor Networks (EWSN 2015), Porto, Portugal, February 9-11, 2015
Funder
Wireless@kth
Note

QC 20150605

Available from: 2015-05-13 Created: 2015-05-13 Last updated: 2016-04-06Bibliographically approved
7. Evaluating Buffer Management Algorithms for Delay Tolerant Wireless Sensor Networks
Open this publication in new window or tab >>Evaluating Buffer Management Algorithms for Delay Tolerant Wireless Sensor Networks
(English)Manuscript (preprint) (Other academic)
Abstract [en]

One of the challenges in Delay Tolerant Wireless Sensor Networks (DT-WSN), is to handle situations where the available buffer space is insufficient. This is the buffer management problem. In this work, we the buffer management problem, with focus on algorithms to decide what data to discard when buffers are full. We simulate a wide range of network configurations, using a full factorial experiment design. The simulations let us investigate both the relative performance of four buffer management algorithms and the effect of different factors on buffer management performance. The four algorithms we investigate are the two well-known algorithms FIFO and Random Discard, and two Quality of Information based algorithms: an exponential moving average forecasting-based algorithm and the SmartGap algorithm. Our results indicate that certain factors, including mobility model and routing algorithm, have larger influence on relative performance than factors such as link speed and lifetime of data. We also find that the SmartGap buffer management algorithm provides significantly better QoI compared to the alternative algorithms.

Keyword
DTN, WSN, DT-WSN, SmartGap, Simulation, ANOVA
National Category
Telecommunications
Research subject
Computer Science
Identifiers
urn:nbn:se:kth:diva-184497 (URN)
Funder
Wireless@kth
Note

QCR 20160530

Available from: 2016-04-01 Created: 2016-04-01 Last updated: 2016-05-30Bibliographically approved

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Söderman, Pehr

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