1. |
- Ali, Muneeb, et al.
(författare)
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Medium access control issues in sensor networks
- 2006. - 1
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Ingår i: Computer communication review. - : Association for Computing Machinery (ACM). - 0146-4833 .- 1943-5819. ; 36, s. 33-36
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Tidskriftsartikel (refereegranskat)abstract
- Medium access control for wireless sensor networks has been a very active research area for the past couple of years. The sensor networks literature presents an alphabet soup of medium access control protocols with almost all of the works focusing only on energy efficiency. There is much more innovative work to be done at the MAC layer, but current efforts are not addressing the hard unsolved problems. Majority of the works appearing in the literature are "least publishable incremental improvements" over the popular S-MAC [1] protocol. In this paper we present research directions for future medium access research. We identify some open issues and discuss possible solutions.
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2. |
- Bajpai, Vaibhav, et al.
(författare)
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The Dagstuhl Beginners Guide to Reproducibility for Experimental Networking Research
- 2019
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Ingår i: Computer communication review. - New York : Association for Computing Machinery (ACM). - 0146-4833 .- 1943-5819. ; 49:1, s. 24-30
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Reproducibility is one of the key characteristics of good science, but hard to achieve for experimental disciplines like Internet measurements and networked systems. This guide provides advice to researchers, particularly those new to the field, on designing experiments so that their work is more likely to be reproducible and to serve as a foundation for follow-on work by others.
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3. |
- Bodin, Ulf, et al.
(författare)
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Load-tolerant differentiation with active queue management
- 2000
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Ingår i: Computer communication review. - : Association for Computing Machinery (ACM). - 0146-4833 .- 1943-5819. ; 30:3, s. 4-16
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Tidskriftsartikel (refereegranskat)abstract
- Current work in the IETF aims at providing service differentiation on the Internet. One proposal is to provide loss differentiation by assigning levels of drop procedence to IP packets. In this paper, we evaluate the active queue management (AQM) mechanisms RED In and Out (RIO) and Weighted RED (WRED) in providing levels of drop precedence under different loads. For low drop precedence traffic, FIO and WRED can be configured to offer sheltering (i.e., low drop precedence traffic is protected from losses caused by higher drop precedence traffic). However, if traffic control fails or is inaccurate, such configurations can cause starvation of traffic at high drop precedence levels. Configuring WRED to instead offer relative differentiation can eliminate the risk of starvation. However, WRED cannot, without reconfiguration, both offer sheltering when low drop precedence traffic is properly controlled and avoid starvation at overload of low drop precedence traffic. To achieve this, we propose a new AQM mechanism, WRED with Thresholds (WRT). The benefit of WRT is that, without reconfiguration, it offers sheltering when low drop precedence traffic is properly controlled and relative differentiation otherwise. We present simulations showing that WRT has these properties.
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4. |
- Bogdanov, Kirill, et al.
(författare)
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Toward Automated Testing of Geo-Distributed Replica Selection Algorithms
- 2015
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Ingår i: Computer communication review. - : Association for Computing Machinery (ACM). - 0146-4833 .- 1943-5819. ; 45:4, s. 89-90
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Tidskriftsartikel (refereegranskat)abstract
- Many geo-distributed systems rely on a replica selection algorithms to communicate with the closest set of replicas. Unfortunately, the bursty nature of the Internet traffic and ever changing network conditions present a problem in identifying the best choices of replicas. Suboptimal replica choices result in increased response latency and reduced system performance. In this work we present GeoPerf, a tool that tries to automate testing of geo-distributed replica selection algorithms. We used GeoPerf to test Cassandra and MongoDB, two popular data stores, and found bugs in each of these systems.
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5. |
- Degermark, Mikael, et al.
(författare)
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Small forwarding tables for fast routing lookups
- 1997
-
Ingår i: Computer communication review. - Luleå : Luleå tekniska universitet. - 0146-4833 .- 1943-5819. ; 27:4, s. 3-14
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- For some time, the Internet community has believed that it is impossible to do IP routing lookups in software fast enough to support gigabit speeds. IP routing lookups must find the routing entry with the longest matching prefix, a task that has been thought to require hardware support at lookup frequencies of millions per second. We present a forwarding table data structure designed for quick routing lookups. Forwarding tables are small enough to fit in the cache of a conventional general purpose processor. With the table in cache, a 200 MHz Pentium Pro or a 333 MHz Alpha 21164 can perform a few million lookups per second. This means that it is feasible to do a full routing lookup for each IP packet at gigabit speeds without special hardware. The forwarding tables are very small, a large routing table with 40,000 routing entries can be compacted to a forwarding table of 150--160 Kbytes. A lookup typically requires less than 100 instructions on an Alpha, using eight memory references accessing a total of 14 bytes.
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6. |
- Devlic, Alisa
(författare)
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SIP-based context distribution : Does aggregation pay off?
- 2010
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Ingår i: SIGCOMM'10 - Proceedings of the SIGCOMM 2010 Conference. - : Association for Computing Machinery (ACM). - 9781450302012 ; 40:5, s. 35-46
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Konferensbidrag (refereegranskat)abstract
- Context-aware applications need quickly access to current context information, in order to adapt their behavior before this context changes. To achieve this, the context distribution mechanism has to timely discover context sources that can provide a particular context type, then acquire and distribute context information from these sources to the applications that requested this type of information. This paper reviews the state-of-the-art context distribution mechanisms according to identified requirements, then introduces a resource list-based subscription/notification mechanism for context sharing. This SIP-based mechanism enables subscriptions to a resource list containing URIs of multiple context sources that can provide the same context type and delivery of aggregated notifications containing context updates from each of these sources. Aggregation of context is thought to be important as it reduces the network traffic between entities involved in context distribution. However, it introduces an additional delay due to waiting for context updates and their aggregation. To investigate if this aggregation actually pays off, we measured and compared the time needed by an application to receive context updates after subscribing to a particular resource list (using RLS) versus after subscribing to each of the individual context sources (using SIMPLE) for different numbers of context sources. Our results show that RLS aggregation outperforms the SIMPLE presence mechanism with 3 or more context sources, regardless of their context updates size. Database performance was identified as a major bottleneck during aggregation, hence we used in-memory tables & prepared statements, leading to up to 57% database time improvement, resulting in a reduction of the aggregation time by up to 34%. With this reduction and an increase in context size, we pushed the aggregation payoff threshold closer to 2 context sources.
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7. |
- Fayazbakhsh, S. K., et al.
(författare)
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Less pain, most of the gain : Incrementally deployable ICN
- 2013
-
Ingår i: Computer communication review. - : Association for Computing Machinery (ACM). - 0146-4833 .- 1943-5819. - 9781450320566 ; 43:4, s. 147-158
-
Tidskriftsartikel (refereegranskat)abstract
- Information-Centric Networking (ICN) has seen a significant resurgence in recent years. ICN promises benefits to users and service providers along several dimensions (e.g., performance, security, and mobility). These benefits, however, come at a non-trivial cost as many ICN proposals envision adding significant complexity to the network by having routers serve as content caches and support nearest-replica routing. This paper is driven by the simple question of whether this additional complexity is justified and if we can achieve these benefits in an incrementally deployable fashion. To this end, we use trace-driven simulations to analyze the quantitative benefits attributed to ICN (e.g., lower latency and congestion). Somewhat surprisingly, we find that pervasive caching and nearest-replica routing are not fundamentally necessary - -most of the performance benefits can be achieved with simpler caching architectures. We also discuss how the qualitative benefits of ICN (e.g., security, mobility) can be achieved without any changes to the network. Building on these insights, we present a proof-of-concept design of an incrementally deployable ICN architecture.
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8. |
- Ghodsi, Ali, et al.
(författare)
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Multi-Resource Fair Queueing for Packet Processing
- 2012
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Ingår i: Computer communication review. - : Association for Computing Machinery (ACM). - 0146-4833 .- 1943-5819. ; 42:4, s. 1-12
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Tidskriftsartikel (refereegranskat)abstract
- Middleboxes are ubiquitous in today's networks and perform a variety of important functions, including IDS, VPN, firewalling, and WAN optimization. These functions differ vastly in their requirements for hardware resources (e.g., CPU cycles and memory bandwidth). Thus, depending on the functions they go through, different flows can consume different amounts of a middlebox's resources. While there is much literature on weighted fair sharing of link bandwidth to isolate flows, it is unclear how to schedule multiple resources in a middlebox to achieve similar guarantees. In this paper, we analyze several natural packet scheduling algorithms for multiple resources and show that they have undesirable properties. We propose a new algorithm, Dominant Resource Fair Queuing (DRFQ), that retains the attractive properties that fair sharing provides for one resource. In doing so, we generalize the concept of virtual time in classical fair queuing to multi-resource settings. The resulting algorithm is also applicable in other contexts where several resources need to be multiplexed in the time domain.
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9. |
- Grönvall, Björn
(författare)
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Scalable multicast forwarding
- 2002
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Ingår i: Computer communication review. - : Association for Computing Machinery (ACM). - 0146-4833 .- 1943-5819. ; 32:1, s. 68-
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Tidskriftsartikel (refereegranskat)
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10. |
- Hollick, Matthias, et al.
(författare)
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Toward a Taxonomy and Attacker Model for Secure Routing Protocols
- 2017
-
Ingår i: Computer communication review. - : Association for Computing Machinery (ACM). - 0146-4833 .- 1943-5819. ; 47:1, s. 43-48
-
Tidskriftsartikel (refereegranskat)abstract
- A secure routing protocol represents a foundational building block of a dependable communication system. Unfortunately, currently no taxonomy exists to assist in the design and analysis of secure routing protocols. Based on the Dagstuhl Seminar 15102, this paper initiates the study of more structured approaches to describe secure routing protocols and the corresponding attacker models, in an effort to better understand existing secure routing protocols, and to provide a framework for designing new protocols. We decompose the routing system into its key components based on a functional model of routing. This allows us to classify possible attacks on secure routing protocols. Using our taxonomy, we observe that the most eective attacks target the information in the control plane. Accordingly, unlike classic attackers whose capabilities are often described in terms of computation complexity we propose to classify the power of an attacker with respect to the reach, that is, the extent to which the attacker can influence the routing information indirectly, beyond the locations under its direct control.
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11. |
- Holme, Petter, et al.
(författare)
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An integrated model of traffic, geography and economy in the internet
- 2008
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Ingår i: Computer communication review. - 0146-4833 .- 1943-5819. ; 38:3, s. 7-15
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Tidskriftsartikel (refereegranskat)abstract
- Modeling Internet growth is important both for understanding the current network and to predict and improve its future. To date, Internet models have typically attempted to explain a subset of the following characteristics: network structure, traffic flow, geography, and economy. In this paper we present a discrete, agent-based model, that integrates all of them. We show that the model generates networks with topologies, dynamics, and more speculatively spatial distributions that are similar to the Internet.
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12. |
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13. |
- Koponen, Teemu, et al.
(författare)
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Architecting for Innovation
- 2011
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Ingår i: Computer communication review. - : Association for Computing Machinery (ACM). - 0146-4833 .- 1943-5819. ; 41:3, s. 24-36
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Tidskriftsartikel (refereegranskat)abstract
- We argue that the biggest problem with the current Internet architecture is not a particular functional deficiency, but its inability to accommodate innovation. To address this problem we propose a minimal architectural "framework" in which comprehensive architectures can reside. The proposed Framework for Internet Innovation (FII) - which is derived from the simple observation that network interfaces should be extensible and abstract - allows for a diversity of architectures to coexist, communicate, and evolve. We demonstrate FII's ability to accommodate diversity and evolution with a detailed examination of how information flows through the architecture and with a skeleton implementation of the relevant interfaces.
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14. |
- Krishnamoorthi, Vengatanathan, 1987-, et al.
(författare)
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Empowering the Creative User : Personalized HTTP-based Adaptive Streaming of Multi-path Nonlinear Video
- 2013
-
Ingår i: Computer communication review. - New York : Association for Computing Machinery (ACM). - 0146-4833 .- 1943-5819. ; 43:4, s. 591-596
-
Tidskriftsartikel (refereegranskat)abstract
- This paper presents the design, implementation, and validation of a novel system that supports streaming and playout of personalized, multi-path, nonlinear video. In contrast to regular video, in which the file content is played sequentially, our design allows multiple nonlinear video sequences of the underlying (linear) video to be stitched together and played in any personalized order, and clients can be provided multiple path choices. The design combines the ideas of HTTP-based adaptive streaming (HAS) and multi-path nonlinear video. Personalization of the content is achieved with the use of a customized metafile, which is downloaded separately from the underlying media and the manifest file that defines the HAS structure. An extension to the user interface allows path choices to be presented to and made by the user. Novel buffer management and prefetching policies are used to ensure seamless uninterrupted playback regardless of client path choices, even under scenarios in which clients defer their choices until the last possible moment. Our solution allows creative home users to easily create their own multi-path nonlinear video, opening the door to an endless possibility of new opportunities and media forms.
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15. |
- Landström, Sara, et al.
(författare)
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Reducing the TCP Acknowledgment Frequency
- 2007
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Ingår i: Computer communication review. - : Association for Computing Machinery (ACM). - 0146-4833 .- 1943-5819. ; 37:3, s. 5-16
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Tidskriftsartikel (refereegranskat)abstract
- Delayed acknowledgments were introduced to conserve net- work and host resources. Further reduction of the acknowl- edgment frequency can be motivated in the same way. How- ever, reducing the dependency on frequent acknowledgments in TCP is difficult because acknowledgments support reli- able delivery, loss recovery, clock out new segments, and serve as input when determining an appropriate sending rate. Our results show that in scenarios where there are no ob- vious advantages of reducing the acknowledgment frequency, performance can be maintained although fewer acknowledg- ments are sent. Hence, there is a potential for reducing the acknowledgment frequency more than is done through de- layed acknowledgments today. Advancements in TCP loss recovery is one of the key reasons that the dependence on frequent acknowledgments has decreased. We propose and evaluate an end-to-end solution, where four acknowledgments per send window are sent. The sender compensates for the reduced acknowledgment frequency us- ing a form of Appropriate Byte Counting. The proposal also includes a modification of fast loss recovery to avoid frequent timeouts.
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16. |
- Lindgren, Anders, et al.
(författare)
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ExtremeCom: To Boldly Go Where No One Has Gone Before
- 2011. - 7
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Ingår i: Computer communication review. - : ACM. - 0146-4833 .- 1943-5819. ; 41, s. 54-59
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Tidskriftsartikel (refereegranskat)abstract
- Research on networks for challenged environments has become a major research area recently. There is however a lack of true understanding among networking researchers about what such environments really are like. In this paper we give an introduction to the ExtremeCom series of workshops that were created to overcome this limitation. We will discuss the motivation behind why the workshop series was created, give some summaries of the two workshops that have been held, and discuss the lessons that we have learned from them.
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17. |
- Lundén, Marcus, et al.
(författare)
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The Politecast Communication Primitive for Low-Power Wireless
- 2011. - 10
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Ingår i: Computer communication review. - : ACM. - 0146-4833 .- 1943-5819. ; 41, s. 32-37
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Tidskriftsartikel (refereegranskat)abstract
- In low-power wireless networks, nodes need to duty cycle their radio transceivers to achieve a long system lifetime. Counter-intuitively, in such networks broadcast becomes expensive in terms of energy and bandwidth since all neighbors must be woken up to receive broadcast messages. We argue that there is a class of traffic for which broadcast is overkill: periodic redundant transmissions of semi-static information that is already known to all neighbors, such as neighbor and router advertisements. Our experiments show that such traffic can account for as much as 20% of the network power consumption. We argue that this calls for a new communication primitive and present politecast, a communication primitive that allows messages to be sent without explicitly waking neighbors up. We have built two systems based on politecast: a low-power wireless mobile toy and a full-scale low-power wireless network deployment in an art gallery and our experimental results show that politecast can provide up to a four-fold lifetime improvement over broadcast.
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18. |
- Marcos, Pedro, et al.
(författare)
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A Survey on the Current Internet Interconnection Practices
- 2020
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Ingår i: Computer communication review. - : Association for Computing Machinery (ACM). - 0146-4833 .- 1943-5819. ; 50:1, s. 10-17
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Tidskriftsartikel (refereegranskat)abstract
- The Internet topology has significantly changed in the past years. Today, it is richly connected and flattened. Such a change has been driven mostly by the fast growth of peering infrastructures and the expansion of Content Delivery Networks as alternatives to reduce interconnection costs and improve traffic delivery performance. While the topology evolution is perceptible, it is unclear whether or not the interconnection process has evolved or if it continues to be an ad-hoc and lengthy process. To shed light on the current practices of the Internet interconnection ecosystem and how these could impact the Internet, we surveyed more than 100 network operators and peering coordinators. We divide our results into two parts: (i)(i) the current interconnection practices, including the steps of the process and the reasons to establish new interconnection agreements or to renegotiate existing ones, and the parameters discussed by network operators. In part (ii)(ii), we report the existing limitations and how the interconnection ecosystem can evolve in the future. We show that despite the changes in the topology, interconnecting continues to be a cumbersome process that usually takes days, weeks, or even months to complete, which is in stark contrast with the desire of most operators in reducing the interconnection setup time. We also identify that even being primary candidates to evolve the interconnection process, emerging on-demand connectivity companies are only fulfilling part of the existing gap between the current interconnection practices and the network operators' desires.
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19. |
- Ngai, Edith, et al.
(författare)
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Can we make a cake and eat it too? : A discussion of ICN security and privacy
- 2017
-
Ingår i: Computer communication review. - : Association for Computing Machinery (ACM). - 0146-4833 .- 1943-5819. ; 47:1, s. 49-54
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- In recent years, Information-centric Networking (ICN) has received much attention from both academic and industry participants. ICN offers data-centric inter-networking that is radically different from today's host-based IP networks. Security and privacy features on today's Internet were originally not present and have been incrementally retrofitted over the last 35 years. As such, these issues have become increasingly important as ICN technology gradually matures towards real-world deployment. Thus, while ICN-based architectures (e.g., NDN, CCNx, etc.) are still evolving, it is both timely and important to explore ICN security and privacy issues as well as devise and assess possible mitigation techniques.This report documents the highlights and outcomes of the Dagstuhl Seminar 16251 on ``Information-centric Networking and Security.'' The goal of which was to bring together researchers to discuss and address security and privacy issues particular to ICN-based architectures. Upon finishing the three-day workshop, the outlook of ICN is still unclear. Many unsolved and ill-addressed problems remain, such as namespace and identity management, object security and forward secrecy, and privacy. Regardless of the fate of ICN, one thing is certain: much more research and practical experience with these systems is needed to make progress towards solving these arduous problems.
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20. |
- Oljira, Dejene Boru, et al.
(författare)
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Validating the Sharing Behavior and Latency Characteristics of the L4S Architecture
- 2020
-
Ingår i: Computer communication review. - : ACM Digital Library. - 0146-4833 .- 1943-5819. ; 50:2, s. 37-44
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Tidskriftsartikel (refereegranskat)abstract
- The strict low-latency requirements of applications such as virtual reality, online gaming, etc., can not be satisfied by the current internet. This is due to the characteristics of classic TCP such as Reno and TCP Cubic which induce high queuing delays when used for capacity-seeking traffic, which in turn results in unpredictable latency. The Low Latency, Low Loss, Scalable throughput (L4S) architecture addresses this problem by combining scalable congestion controls such as DCTCP and TCP Prague with early congestion signaling from the network. It defines a Dual Queue Coupled (DQC) AQM that isolates low-latency traffic from the queuing delay of classic traffic while ensuring the safe co-existence of scalable and classic flows on the global Internet. In this paper, we benchmarktheDualPI2 scheduler, a reference implementation of DQC AQM, to validate some of the experimental result(s) reported in the previous works that demonstrate the co-existence of scalable and classic congestion controls and its low-latency service. Our results validate the co-existence of scalable and classic flows using DualPI2 Singlequeue (SingleQ) AQM, and queue latency isolation of scalable flows using DualPI2 Dual queue (DualQ) AQM. However, the rate or win-dow fairness between DCTCP without fair-queuing (FQ) pacing and TCP Cubic using DualPI2 DualQ AQM deviates from the original results. We attribute the difference in our results and the original results to the sensitivity of the L4S architecture to traffic bursts and the burst sending pattern of the Linux kernel.
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21. |
- Rajiullah, Mohammad, 1981-, et al.
(författare)
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An Evaluation of Tail Loss Recovery Mechanisms for TCP
- 2015
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Ingår i: Computer communication review. - USA : ACM Special Interest Group on Computer Science Education. - 0146-4833 .- 1943-5819. ; 45:1, s. 6-11
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Tidskriftsartikel (refereegranskat)abstract
- Interactive applications do not require more bandwidth to go faster. Instead, they require less latency. Unfortunately, the current design of transport protocols such as TCP limits possible latency reductions. In this paper we evaluate and compare different loss recovery enhancements to fight tail loss latency. The two recently proposed mechanisms "RTO Restart" (RTOR) and "Tail Loss Probe" (TLP) as well as a new mechanism that applies the logic of RTOR to the TLP timer management (TLPR) are considered. The results show that the relative performance of RTOR and TLP when tail loss occurs is scenario dependent, but with TLP having potentially larger gains. The TLPR mechanism reaps the benefits of both approaches and in most scenarios it shows the best performance.
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22. |
- Reda, Waleed, 1989-, et al.
(författare)
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Path Persistence in the Cloud: A Study of the Effects of Inter-Region Traffic Engineering in a Large Cloud Provider's Network
- 2020
-
Ingår i: Computer communication review. - New York, NY, United States : Association for Computing Machinery (ACM). - 0146-4833 .- 1943-5819. ; 50:2, s. 11-23
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Tidskriftsartikel (refereegranskat)abstract
- A commonly held belief is that traffic engineering and routing changes are infrequent. However, based on our measurements over a number of years of traffic between data centers in one of the largest cloud provider's networks, we found that it is common for flows to change paths at ten-second intervals or even faster. These frequent path and, consequently, latency variations can negatively impact the performance of cloud applications, specifically, latency-sensitive and geo-distributed applications.Our recent measurements and analysis focused on observing path changes and latency variations between different Amazon aws regions. To this end, we devised a path change detector that we validated using both ad hoc experiments and feedback from cloud networking experts. The results provide three main insights: (1) Traffic Engineering (TE) frequently moves (TCP and UDP) flows among network paths of different latency, (2) Flows experience unfair performance, where a subset of flows between two machines can suffer large latency penalties (up to 32% at the 95th percentile) or excessive number of latency changes, and (3) Tenants may have incentives to selfishly move traffic to low latency classes (to boost the performance of their applications). We showcase this third insight with an example using rsync synchronization.To the best of our knowledge, this is the first paper to reveal the high frequency of TE activity within a large cloud provider's network. Based on these observations, we expect our paper to spur discussions and future research on how cloud providers and their tenants can ultimately reconcile their independent and possibly conflicting objectives. Our data is publicly available for reproducibility and further analysis at http://goo.gl/25BKte.
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23. |
- Roverso, Roberto, et al.
(författare)
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On HTTP live streaming in large enterprises
- 2013
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Ingår i: Computer communication review. - : Association for Computing Machinery (ACM). - 0146-4833 .- 1943-5819. - 9781450320566 ; 43:4, s. 489-490
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Tidskriftsartikel (refereegranskat)abstract
- In this work, we present a distributed caching solution which addresses the problem of efficient delivery of HTTP live streams in large private networks. With our system, we have conducted tests on a number of pilot deployments. The largest of them, with 3000 concurrent viewers, consistently showed that our system saves more than 90% of traffic towards the source of the stream while providing the same quality of user experience of a CDN. Another result is that our solution was able to reduce the load on the bottlenecks in the network by an average of 91.6%.
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24. |
- Tschudin, Christian, et al.
(författare)
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Network Pointers
- 2003
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Ingår i: ACM SIGCOMM Computer Communication Review. - 0146-4833. ; 33:1, s. 23 - 28
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Tidskriftsartikel (refereegranskat)
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25. |
- Tschudin, Christian, et al.
(författare)
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Network Pointers
- 2002
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Ingår i: SIGCOMM Communications Review. - 0146-4833. ; 33:1
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Tidskriftsartikel (refereegranskat)
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