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- AT, Andersen, et al.
(författare)
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A partially-blocking queueing system with CBR/VBR and ABR/UBR arrival streams
- 2002
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Ingår i: Telecommunications Systems. - : Baltzer Academic Publisher. - 1018-4864 .- 1572-9451. ; 19:1, s. 75-99
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Tidskriftsartikel (refereegranskat)abstract
- In this paper we consider an ATM transmission link., to which CBR or VBR and ABR or UBR calls arrive according to independent Poisson processes. CBR/VBR calls (characterized by their equivalent bandwidth) are blocked and leave the system if the available link capacity is less than required at the time of arrival. ABR/UBR calls, however, accept partial blocking, meaning that they may enter service even if the available capacity is less than the specified required peak bandwidth, but greater than the so called minimal accepted bandwidth. Partially blocked ABR/UBR calls instead experience longer service time, since smaller given bandwidth entails proportionally longer time spent in the system, as first suggested in [3] and analyzed in details herein. Throughout the life time of an ABR/UBR connection, its bandwidth consumption fluctuates in accordance with the current load on the link but always at the highest possible value up to their peak bandwidth (greedy sources). Additionally, if this minimal accepted bandwidth is unavailable at the time of arrival, ABR/UBR calls are allowed to wait in a finite queue. This system is modeled by a Continuous Time Markov Chain (CTMC) and the CBR/VBR and ABR/UBR blocking probabilities and the mean ABR/UBR waiting- and service times are derived.
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- G, Fodor, et al.
(författare)
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On providing blocking probability and throughput guarantees in a multi-service environment
- 2002
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Ingår i: International Journal of Communication Systems. - : WILEY. - 1074-5351 .- 1099-1131. ; 15:4, s. 257-285
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Tidskriftsartikel (refereegranskat)abstract
- As the Internet evolves from a packet network supporting a single best effort service class towards an integrated infrastructure supporting several service classes-some with QoS guarantees-there is a growing interest in the introduction of admission control and in devising bandwidth sharing strategies, which meet the diverse needs of QoS-assured and elastic services. In this paper we show that the extension of the classical multi-rate loss model is possible in a way that makes it useful in the performance analysis of a future admission control based Internet that supports traffic with peak rate guarantee as well as elastic traffic. After introducing the model, it is applied for the analysis of a single link, where it sheds light on the trade-off between blocking probability and throughput. For the investigation of this trade-off, we introduce the throughput-threshold constraint, which bounds the probability that the throughput of a traffic flow drops below a predefined threshold. Finally, we use the model to determine the optimal parameter set of the popular partial overlap link allocation policy: we propose a computationally efficient algorithm that provides blocking probability- and throughput guarantees. We conclude that the model and the numerical results provide important insights in traffic engineering in the Internet. Copyright (C) 2002 John Wiley Sons, Ltd.
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| 8. |
- S, Racz, et al.
(författare)
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Link capacity sharing between guaranteed- and best effort services on an ATM transmission link under GoS constraints
- 2001
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Ingår i: Telecommunications Systems. - 1018-4864 .- 1572-9451. ; 17:1, s. 93-114
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Tidskriftsartikel (refereegranskat)abstract
- While link allocation policies in multi-rate circuit switched loss models have drawn much attention in recent years, it is still an open question how to share the link capacity between service classes in a fair manner. In particular, when an ATM link is offered calls from service classes with/without strict QoS guarantees one is interested in link capacity sharing policies that maximize throughput and keep the per-class blocking probabilities under some GoS constraints. In this paper we propose a model and associated computational technique for an ATM transmission link to which CBR/VBR and ABR classes offer calls. We also propose a simple link allocation rule which takes into account blocking probability constraints for the CBR/VBR calls and a throughput constraint for the ABR calls and attempts to minimize the blocking probability of ABR calls. Numerical examples demonstrate the effectiveness of the policy and of the applied computational technique.
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