Change search
ReferencesLink to record
Permanent link

Direct link
On the Bleeding Edge: Debloating Internet Access Networks
Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science. (DISCO)ORCID iD: 0000-0001-5241-6815
2016 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

As ever more devices are connected to the internet, and applications turn ever more interactive, it becomes more important that the network can be counted on to respond reliably and without unnecessary delay. However, this is far from always the case today, as there can be many potential sources of unnecessary delay. In this thesis we focus on one of them: Excess queueing delay in network routers along the path, also known as bufferbloat.

We focus on the home network, and treat the issue in three stages. We examine latency variation and queueing delay on the public internet and show that significant excess delay is often present. Then, we evaluate several modern AQM algorithms and packet schedulers in a residential setting, and show that modern AQMs can almost entirely eliminate bufferbloat and extra queueing latency for wired connections, but that they are not as effective for WiFi links. Finally, we go on to design and implement a solution for bufferbloat at the WiFi link, and also design a workable scheduler-based solution for realising airtime fairness in WiFi.

Also included in this thesis is a description of Flent, a measurement tool used to perform most of the experiments in the other papers, and also used widely in the bufferbloat community.

Place, publisher, year, edition, pages
Karlstad: Karlstad University Press, 2016. , 20 p.
Series
Karlstad University Studies, ISSN 1403-8099 ; 2016:49
Keyword [en]
Bufferbloat, WiFi, AQM, queueing, network measurement, performance evaluation, fairness
National Category
Computer Science
Research subject
Computer Science
Identifiers
URN: urn:nbn:se:kau:diva-47001ISBN: 978-91-7063-732-2OAI: oai:DiVA.org:kau-47001DiVA: diva2:1044014
Presentation
2016-12-06, 1B309 (Sjöströmsalen), Karlstads Universitet, Universitetsgatan 2, Karlstad, 13:15 (English)
Opponent
Supervisors
Available from: 2016-11-16 Created: 2016-11-01 Last updated: 2016-11-16Bibliographically approved
List of papers
1. Measuring Latency Variation in the Internet
Open this publication in new window or tab >>Measuring Latency Variation in the Internet
2016 (English)Conference paper (Refereed)
Abstract [en]

We analyse two complementary datasets to quantify the latency variation experienced by internet end-users: (i) a large-scale active measurement dataset (from the Measurement Lab Network Diagnostic Tool) which shed light on long-term trends and regional differences; and (ii) passive measurement data from an access aggregation link which is used to analyse the edge links closest to the user.

The analysis shows that variation in latency is both common and of significant magnitude, with two thirds of samples exceeding 100\,ms of variation. The variation is seen within single connections as well as between connections to the same client. The distribution of experienced latency variation is heavy-tailed, with the most affected clients seeing an order of magnitude larger variation than the least affected. In addition, there are large differences between regions, both within and between continents. Despite consistent improvements in throughput, most regions show no reduction in latency variation over time, and in one region it even increases.

We examine load-induced queueing latency as a possible cause for the variation in latency and find that both datasets readily exhibit symptoms of queueing latency correlated with network load. Additionally, when this queueing latency does occur, it is of significant magnitude, more than 200\,ms in the median. This indicates that load-induced queueing contributes significantly to the overall latency variation.

Keyword
Latency, Bufferbloat, Access Network Performance
National Category
Computer Science
Research subject
Computer Science
Identifiers
urn:nbn:se:kau:diva-46999 (URN)10.1145/2999572.2999603 (DOI)978-1-4503-4292-6/16/12 (ISBN)
Conference
ACM CoNEXT 2016
Projects
SIDUS READY
Funder
Knowledge Foundation, 317700
Available from: 2016-11-01 Created: 2016-11-01 Last updated: 2016-11-01
2. The Good, the Bad and the WiFi: Modern AQMs in a residential setting
Open this publication in new window or tab >>The Good, the Bad and the WiFi: Modern AQMs in a residential setting
2015 (English)In: Computer Networks, ISSN 1389-1286, E-ISSN 1872-7069, Vol. 89, 90-106 p.Article in journal (Refereed) Published
Abstract [en]

Several new active queue management (AQM) and hybrid AQM/fairness queueing algorithms have been proposed recently. They seek to ensure low queueing delay and high network goodput without requiring parameter tuning of the algorithms themselves. However, extensive experimental evaluations of these algorithms are still lacking. This paper evaluates a selection of bottleneck queue management schemes in a test-bed representative of residential Internet connections of both symmetrical and asymmetrical bandwidths as well as WiFi. Latency under load and the performance of VoIP and web traffic patterns are evaluated under steady state conditions. Furthermore, the impact of the algorithms on fairness between TCP flows with different RTTs, and also the transient behaviour of the algorithms at flow startup is examined. The results show that while the AQM algorithms can significantly improve steady state performance, they exacerbate TCP flow unfairness. In addition, the evaluated AQMs severely struggle to quickly control queueing latency at flow startup, which can lead to large latency spikes that hurt the perceived performance. The fairness queueing algorithms almost completely alleviate the algorithm performance problems, providing the best balance of low latency and high throughput in the tested scenarios. However, on WiFi the performance of all the tested algorithms is hampered by large amounts of queueing in lower layers of the network stack inducing significant latency outside of the algorithms’ control.

Place, publisher, year, edition, pages
Elsevier, 2015
Keyword
Active queue management, Fairness queueing, Bufferbloat, Latency, Performance measurement, Wireless networks
National Category
Communication Systems
Research subject
Computer Science
Identifiers
urn:nbn:se:kau:diva-37954 (URN)10.1016/j.comnet.2015.07.014 (DOI)000361403600007 ()
Available from: 2015-09-16 Created: 2015-09-16 Last updated: 2016-11-01Bibliographically approved
3. Ending the Anomaly: Achieving Low Latency and Airtime Fairness in WiFi
Open this publication in new window or tab >>Ending the Anomaly: Achieving Low Latency and Airtime Fairness in WiFi
Show others...
(English)Manuscript (preprint) (Other academic)
National Category
Computer Science
Identifiers
urn:nbn:se:kau:diva-47000 (URN)
Available from: 2016-11-01 Created: 2016-11-01 Last updated: 2016-11-01
4. Flent: The FLExible Network Tester
Open this publication in new window or tab >>Flent: The FLExible Network Tester
2015 (English)Conference paper (Other academic)
National Category
Computer Science
Research subject
Computer Science
Identifiers
urn:nbn:se:kau:diva-43364 (URN)
Conference
The 11th Swedish National Computer Networking Workshop (SNCNW), Karlstad, Sweden, May 28–29, 2015
Available from: 2016-06-19 Created: 2016-06-19 Last updated: 2016-11-24Bibliographically approved

Open Access in DiVA

fulltext(384 kB)124 downloads
File information
File name FULLTEXT01.pdfFile size 384 kBChecksum SHA-512
f2751463491f07e12daf69720d97e530edf58bdac08afb02b80bf2f040f53dabe6db626012f43957a108a2c10b6c208588b34de6091c24d5ffda4b0008f50259
Type fulltextMimetype application/pdf

Search in DiVA

By author/editor
Høiland-Jørgensen, Toke
By organisation
Department of Mathematics and Computer Science
Computer Science

Search outside of DiVA

GoogleGoogle Scholar
Total: 124 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Total: 804 hits
ReferencesLink to record
Permanent link

Direct link