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Optimal file splitting for wireless networks with concurrent access
 Lecture Notes in Computer Science
, 2009
"... Abstract. The fundamental limits on channel capacity form a barrier to the sustained growth on the use of wireless networks. To cope with this, multipath communication solutions provide a promising means to improve reliability and boost Quality of Service (QoS) in areas that are covered by a multit ..."
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Abstract. The fundamental limits on channel capacity form a barrier to the sustained growth on the use of wireless networks. To cope with this, multipath communication solutions provide a promising means to improve reliability and boost Quality of Service (QoS) in areas that are covered by a multitude of wireless access networks. Today, little is known about how to effectively exploit this potential. Motivated by this, we consider N parallel communication networks, each of which is modeled as a processor sharing (PS) queue that handles two types of traffic: foreground and background. We consider a foreground traffic stream of files, each of which is split into N fragments according to a fixed splitting rule (α1,..., αN), where P αi = 1 and αi ≥ 0 is the fraction of the file that is directed to network i. Upon completion of transmission of all fragments of a file, it is reassembled at the receiving
On Comparing the Performance of Dynamic MultiNetwork Optimizations
"... AbstractWith a large variety of wireless access technologies available, multihomed devices may strongly improve the performance and reliability of communication when using multiple networks simultaneously. A key question for the practical application of multipath strategies is the granularity at ..."
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AbstractWith a large variety of wireless access technologies available, multihomed devices may strongly improve the performance and reliability of communication when using multiple networks simultaneously. A key question for the practical application of multipath strategies is the granularity at which the traffic streams should be dispersed among the available networks. This level of granularity may be expected to have a major impact on both the efficiency and complexity of practical realizations. Motivated by this, we compare two dynamic strategies that operate at different levels of granularity. The first strategy, which we call network selection, requires little operational complexity and dynamically assigns an arriving application data transfer to the network that delivers the highest expected performance. Our second strategy, which we call trafficsplitting, is of higher complexity and aims to optimally split individual data transfers among the available networks. To this end, we (1) develop quantitative models that describe the performance of both strategies, (2) determine the (near)optimal algorithms for both strategies, and (3) validate the efficiency and practical usefulness of the algorithms via extensive network simulations and experiments in a reallife testbed environment. These experimental results show that the optimal strategies obtained from the theoretical models lead to extremely wellperforming solutions in practical circumstances. Moreover, the results show that the splitting of data transfers, which is easy to embed in the network requiring no information on the number of flows in the system, leads to a much better performance compared to dynamic network selection.
Optimal file splitting for wireless networks with concurrent access
"... Abstract. The fundamental limits on channel capacity form a barrier to the sustained growth on the use of wireless networks. To cope with this, multipath communication solutions provide a promising means to improve reliability and boost Quality of Service (QoS) in areas that are covered by a multi ..."
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Abstract. The fundamental limits on channel capacity form a barrier to the sustained growth on the use of wireless networks. To cope with this, multipath communication solutions provide a promising means to improve reliability and boost Quality of Service (QoS) in areas that are covered by a multitude of wireless access networks. Today, little is known about how to effectively exploit this potential. Motivated by this, we consider N parallel communication networks, each of which is modeled as a processor sharing (PS) queue that handles two types of traffic: foreground and background. We consider a foreground traffic stream of files, each of which is split into N fragments according to a fixed splitting rule (α1, . . . , αN ), where P αi = 1 and αi ≥ 0 is the fraction of the file that is directed to network i. Upon completion of transmission of all fragments of a file, it is reassembled at the receiving end. The background streams use dedicated networks without being split. We study the sojourn time tail behavior of the foreground traffic. For the case of light foreground traffic and regularly varying foreground filesize distributions, we obtain a reducedload approximation (RLA) for the sojourn times, similar to that of a single PSqueue. An important implication of the RLA is that the tailoptimal splitting rule is simply to choose αi proportional to ci − ρi, where ci is the capacity of network i and ρi is the load offered to network i by the corresponding background stream. This result provides a theoretical foundation for the effectiveness of such a simple splitting rule. Extensive simulations demonstrate that this simple rule indeed performs well, not only with respect to the tail asymptotics, but also with respect to the mean sojourn times. The simulations further support our conjecture that the same splitting rule is also tailoptimal for nonlight foreground traffic. Finally, we observe nearinsensitivity of the mean sojourn times with respect to the filesize distribution.
Efficient Traffic Splitting in Parallel TCPBased Wireless Networks: Modelling and Experimental Evaluation
"... Abstract—The concurrent use of networks provides a powerful means to boost performance in areas covered by multiple networks where only limited bandwidth is available. However, despite its enormous potential for performance improvement only little is known about how to effectively exploit the potent ..."
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Abstract—The concurrent use of networks provides a powerful means to boost performance in areas covered by multiple networks where only limited bandwidth is available. However, despite its enormous potential for performance improvement only little is known about how to effectively exploit the potential for performance improvement in practical deployments. This raises the need for trafficsplittingandreassembly algorithms that are effective, yet simple and easytodeploy. Motivated by this, we first propose a simple analytic flowlevel model, called the Concurrent Access Network (CAN) model, that optimally splits traffic in the idealized situation where there is full state information at infinitely finegrained time granularity, leading to zero synchronization delay during the reassembly phase. Next, we present a new splitting algorithm for TCPbased networks that uses a simple score function to make onthefly decisions on the routing of individual TCP segments, based on the measured perconnection RTT, transmissionbuffer content and throughput. Then, we use the CANmodel as a benchmark to evaluate the effectiveness and practical usefulness of the scorefunction based algorithm on real TCP networks in a testlab environment. Extensive lab experimentation demonstrates that this scorefunction based splitting of TCP traffic is extremely efficient, leads to closetooptimal responsetime performance and is easily deployable.
Probability, Networks and Algorithms PNA Probability, Networks and Algorithms
, 2006
"... A fluid system with coupled input and output, and its application to bottlenecks in ad hoc networks ..."
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A fluid system with coupled input and output, and its application to bottlenecks in ad hoc networks
Version 1.0
, 2008
"... 2.1 Model description..................................... 3 ..."
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Optimal job splitting in parallel processor sharing queues
"... The main barrier to the sustained growth of wireless communications is the Shannon limit that applies to the channel capacity. A promising means to realize highcapacity enhancements is the use of multipath communication solutions to improve reliability and network performance in areas that are co ..."
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The main barrier to the sustained growth of wireless communications is the Shannon limit that applies to the channel capacity. A promising means to realize highcapacity enhancements is the use of multipath communication solutions to improve reliability and network performance in areas that are covered by a multitude of overlapping wireless access networks. Despite the enormous potential for capacity enhancements offered by multipath communication techniques, little is known about how to effectively exploit this. Motivated by this, we study a model where jobs are split and downloaded over N multiple parallel networks, each of which is modeled as a processor sharing (PS) queue. Each job is fragmented, according to a fixed splitting rule α = (α1,..., αN) and reassembled at the receiving end. The complex correlation structure between the sojourn times at the PS nodes makes an exact detailed mathematical analysis of the model impossible. Therefore, in this paper we propose a simple and fast approximation for the splitting rule α ∗ that minimizes the expected jobdownload time. Our approximation is validated extensively by simulations. The results show that the outcomes are extremely accurate over a wide range of parameter combinations.