Data networks
A stochastic checkpoint optimization problem
SIAM Journal on Computing
Self-Similar Network Traffic and Performance Evaluation
Self-Similar Network Traffic and Performance Evaluation
Wireless Communications: Principles and Practice
Wireless Communications: Principles and Practice
The Effect of Different Failure Recovery Procedures on the Distribution of Task Completion Times
IPDPS '05 Proceedings of the 19th IEEE International Parallel and Distributed Processing Symposium (IPDPS'05) - Workshop 16 - Volume 17
Measurement-based characterization of 802.11 in a hotspot setting
Proceedings of the 2005 ACM SIGCOMM workshop on Experimental approaches to wireless network design and analysis
On unreliable computing systems when heavy-tails appear as a result of the recovery procedure
ACM SIGMETRICS Performance Evaluation Review - Special issue on the workshop on MAthematical performance Modeling And Analysis (MAMA 2005)
Dynamic packet aggregation to solve performance anomaly in 802.11 wireless networks
Proceedings of the 9th ACM international symposium on Modeling analysis and simulation of wireless and mobile systems
ACM SIGMETRICS Performance Evaluation Review
Adaptive and scalable comparison scheduling
Proceedings of the 2007 ACM SIGMETRICS international conference on Measurement and modeling of computer systems
Is ALOHA causing power law delays?
ITC20'07 Proceedings of the 20th international teletraffic conference on Managing traffic performance in converged networks
File fragmentation over an unreliable channel
INFOCOM'10 Proceedings of the 29th conference on Information communications
Characterizing the spread of correlated failures in large wireless networks
INFOCOM'10 Proceedings of the 29th conference on Information communications
DPLC: dynamic packet length control in wireless sensor networks
INFOCOM'10 Proceedings of the 29th conference on Information communications
Uniform approximation of the distribution for the number of retransmissions of bounded documents
Proceedings of the 12th ACM SIGMETRICS/PERFORMANCE joint international conference on Measurement and Modeling of Computer Systems
Fragmentation algorithms for DTN links
Computer Communications
Retransmissions over correlated channels
ACM SIGMETRICS Performance Evaluation Review - Special issue on the 31st international symposium on computer performance, modeling, measurements and evaluation (IFIPWG 7.3 Performance 2013)
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It was shown recently [7-9], under quite general conditions, that retransmission-based protocols may result in power-law delays and possibly zero throughput even if the distribution of packets (data units) is very concentrated, e.g., exponential or Gaussian. This phenomenon occurs irrespective of whether the cause of retransmissions is due to channel failures in the data link layer [7] or collisions in ALOHA-type protocols in the MAC layer [9]. These theoretical findings are in agreement with empirical measurements in [18], showing that the utilization of the 802.11 protocol is only 40%, basically due to retransmissions. In order to alleviate this problem, we propose a new dynamic packet fragmentation algorithm that can adaptively match channel failure characteristics. This algorithm is based on the mathematical insights developed in [7, 8]. As a first order approximation to the channel dynamics, we assume that the channel is either available for a period of time or unavailable. Then, our fragmentation algorithm divides the original packets into smaller ones whose size is bounded by the kth largest value among the last k+m channel availability periods. We also discuss mechanisms for aggregating smaller packets into larger ones, which, in combination with fragmentation, can further improve the performance. Under the renewal assumptions on the channel dynamics, we prove that our fragmentation method results in k additional moments for the total transmission time until all the fragments are successfully transmitted, i.e., the transmission time has a much more concentrated distribution and, in particular, the channel will always have a positive throughput. In addition, we argue that by tuning the parameter m, the number of introduced new packets can be kept reasonably small as well. Furthermore, we demonstrate through simulations that the superior performance of our fragmentation algorithm extends beyond the renewal assumptions used in the analysis to time varying and/or correlated channels. For practical implementation of the algorithm, we also discuss approaches to measuring the channel availability periods, especially in situations when the channel dynamics may not be directly observable. It is worth mentioning that our algorithm can be used for designing efficient checkpointing schemes in other systems that are prone to failures, e.g., distributed computing systems.