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| 2. |
- Briscoe, Bob, et al.
(författare)
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Reducing Internet Latency : A Survey of Techniques and Their Merits
- 2016
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Ingår i: IEEE Communications Surveys and Tutorials. - : IEEE. - 1553-877X. ; 18:3, s. 2149-2196
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Tidskriftsartikel (refereegranskat)abstract
- Latency is increasingly becoming a performance bottleneck for Internet Protocol (IP) networks, but historically, networks have been designed with aims of maximizing throughput and utilization. This paper offers a broad survey of techniques aimed at tackling latency in the literature up to August 2014, as well as their merits. A goal of this work is to be able to quantify and compare the merits of the different Internet latency reducing techniques, contrasting their gains in delay reduction versus the pain required to implement and deploy them. We found that classifying techniques according to the sources of delay they alleviate provided the best insight into the following issues: 1) The structural arrangement of a network, such as placement of servers and suboptimal routes, can contribute significantly to latency; 2) each interaction between communicating endpoints adds a Round Trip Time (RTT) to latency, particularly significant for short flows; 3) in addition to base propagation delay, several sources of delay accumulate along transmission paths, today intermittently dominated by queuing delays; 4) it takes time to sense and use available capacity, with overuse inflicting latency on other flows sharing the capacity; and 5) within end systems, delay sources include operating system buffering, head-of-line blocking, and hardware interaction. No single source of delay dominates in all cases, and many of these sources are spasmodic and highly variable. Solutions addressing these sources often both reduce the overall latency and make it more predictable.
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| 3. |
- Emmelmann, Marc, et al.
(författare)
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Deliverable 6.2: Trials and experimentation (cycle 2)
- 2020
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Rapport (refereegranskat)abstract
- This deliverable presents the second cycle of trials and experimentation activities executed over 5GENESIS facilities. The document is the continuation of deliverable D6.1, in the sense that it captures tests carried out over the evolved infrastructures hosting 5GENESIS facilities following the methodology defined in D6.1. In this document 8 main KPIs and 4 application specific validation trials achieved, under 123 experiments that performed in total. The tests focus more on i) the evolved 5G infrastructure deployments that includes radio and core elements in non-standalone (NSA) deployment configurations based on commercial and open implementations, and ii) the use of Open 5GENESIS Suite for the execution of the tests.
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| 4. |
- Garcia, Johan
(författare)
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Improving Performance in Heterogeneous Networks: A Transport Layer Centered Approach
- 2005
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The evolution of computer communications and the Internet has led to the emergence of a large number of communication technologies with widely different capabilities and characteristics. While this multitude of technologies provides a wide array of possibilities it also creates a complex and heterogeneous environment for higher-layer communication protocols. Specific link technologies, as well as overall network heterogeneity, can hamper user-perceived performance or impede end-to-end throughput.In this thesis we examine two transport layer centered approaches to improve performance.The first approach addresses the decrease in user satisfaction that occurs when web waiting times become too long. Increased transport layer flexibility with regards to reliability, together with error-resilient image coding, is used to enable a new trade-off. The user is given the possibility to reduce waiting times, at the expense of image fidelity.An experimental examination of this new functionality is provided, with a focus on image-coding aspects. The results show that reduced waiting times can be achieved, and user studies indicate the usefulness of this new trade-off.The second approach concerns the throughput degradations that can occur as a consequence of link and transport layer interactions. An experimental evaluation of the GSM environment shows that when negative interactions do occur, they are coupled to large variability in link layer round-trip times rather than simply to poor radio conditions. Another type of interaction can occur for link layers which expose higher layers to residual bit errors.Residual bit errors create an ambiguity problem for congestion controlled transport layer protocols which cannot correctly determine the cause for a loss. This ambiguity leads to an unnecessary throughput degradation. To mitigate this degradation, loss differentiation and notification mechanisms are proposed and experimentally evaluated from both performance and fairness perspectives. The results show that considerable performance improvements can be realized. However, there are also fairness implications that need to be taken into account since the same mechanisms that improve performance may also lead to unfairness towards flows that do not employ loss differentiation.
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| 5. |
- Kargar Bideh, Minoo, et al.
(författare)
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TADA: An Active Measurement Tool for Automatic Detection of AQM
- 2015
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Ingår i: Proceeding VALUETOOLS'15 Proceedings of the 9th EAI International Conference on Performance Evaluation Methodologies and Tools. - Brussels : The Institute for Computer Sciences, Social Informatics and Telecommunications Engineering. - 9781631900969 ; , s. 55-60
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Konferensbidrag (refereegranskat)abstract
- The problem of overbuffering in today's Internet (termed as bufferbloat) has recently drawn a great amount of attention from the research community. This has led to the development of various active queue management (AQM) schemes. The last years have seen a lot of effort to show the benefits of AQMs over simple tail-drop queuing and to encourage deployment. Yet it is still unknown to what extent AQMs are deployed in the Internet. In this paper, we present an end-to-end active measurement method to detect AQMs on the path bottleneck. We have developed an active measurement tool, named TADA, and evaluated our measurement methodology on a controlled experimental testbed. Experimental results show that the proposed approach provides the basis to identify whether an AQM is deployed on the bottleneck.
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| 6. |
- Krishnamoorthi, Vengatanathan, 1987-
(författare)
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Efficient HTTP-based Adaptive Streaming of Linear and Interactive Videos
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Online video streaming has gained tremendous popularity over recent years and currently constitutes the majority of Internet traffic. As large-scale on-demand streaming continues to gain popularity, several important questions and challenges remain unanswered. This thesis addresses open questions in the areas of efficient content delivery for HTTP-based Adaptive Streaming (HAS) from different perspectives (client, network and content provider) and in the design, implementation, and evaluation of interactive streaming applications over HAS.As streaming usage scales and new streaming services emerge, continuous improvements are required to both the infrastructure and the techniques used to deliver high-quality streams. In the context of Content Delivery Network (CDN) nodes or proxies, this thesis investigates the interaction between HAS clients and proxy caches. In particular, we propose and evaluate classes of content-aware and collaborative policies that take advantage of information that is already available, or share information among elements in the delivery chain, where all involved parties can benefit. Asides from the users’ playback experience, it is also important for content providers to minimize users’ startup times. We have designed and evaluated different classes of client-side policies that can prefetch data from the videos that the users are most likely to watch next, without negatively affecting the currently watched video. To help network providers to monitor and ensure that their customers enjoy good playback experiences, we have proposed and evaluated techniques that can be used to estimate clients’ current buffer conditions. Since several services today stream over HTTPS, our solution is adapted to predict client buffer conditions by only observing encrypted network-level traffic. Our solution allows the operator to identify clients with low-buffer conditions and implement policies that help avoid playback stalls.The emergence of HAS as the de facto standard for delivering streaming content also opens the door to use it to deliver the next generation of streaming services, such as various forms of interactive services. This class of services is gaining popularity and is expected to be the next big thing in entertainment. For the area of interactive streaming, this thesis proposes, models, designs, and evaluates novel streaming applications such as interactive branched videos and multi-video stream bundles. For these applications, we design and evaluate careful prefetching policies that provides seamless playback (without stalls or switching delay) even when interactive branched video viewers defer their choices to the last possible moment and when users switches between alternative streams within multi-video stream bundles. Using optimization frameworks, we design and implement effective buffer management techniques for seamless playback experiences and evaluate several tradeoffs using our policies.
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| 7. |
- Leister, Wolfgang, et al.
(författare)
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An architecture for adaptive multimedia streaming to mobile nodes
- 2008. - 1
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Ingår i: Proceedings of the 6th International Conference on Advances in Mobile Computing and Multimedia.
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Konferensbidrag (refereegranskat)abstract
- We describe the adimus architecture which addresses the problem of maintaining the subjective quality of multimedia streaming for a mobile user. In contrast to other works, the entire end-to-end path of the video stream is considered. Adaptation mechanisms for maintaining quality include time-critical handovers, overlay routing and network estimation techniques. Our architecture is built on overlays that provides the necessary functionality for a video streaming service. The paper highlights the key components that ADIMUS advocates to support quality streaming from server to mobile client.
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| 8. |
- Rajiullah, Mohammad, 1981-, et al.
(författare)
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Mobile Network Performance during the COVID-19 Outbreak from a Testbed Perspective
- 2020
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Konferensbidrag (refereegranskat)abstract
- COVID-19 has changed our lives and continues to have a drastic impact. It forces us to impose restrictive social distancing measures and leads us to rely more on the Internet. Mobile networks become one of the major means to access the Internet for most of us. We investigate the performance of 9 mobile networks in Europe around the time when restrictions were imposed, considering web QoE, throughput, RTT, and signal coverage. Our results show countries’ mobile networks are impacted by COVID-19 (as high as 46 % increase in page load time) at different times based on the outbreak timelines in these countries. Moreover, we find that operators responded properly and the network performance is back to the pre-COVID-19 times.
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