Investigation of dynamic routing and spectrum allocation methods in elastic optical networks

The introduction of flexible frequency grids and advanced modulation techniques to optical transmission, namely an elastic optical network, requires new routing and spectrum allocation techniques. In this paper, we investigate dynamic two-step routing and spectrum allocation (RSA) methods for elastic optical networks. K-shortest path-based methods as well as spectrum allocation methods are analysed and discussed. Experimental verified of the investigated techniques is provided using simulation software. Based on the obtained experimental results, it can be seen that effectiveness of routing and spectrum allocation methods depend on network topologies. Moreover, performance of shortest path first methods improves considerably when a number of candidate paths increases in a topology with high nodal degree

Automatic hidden bypasses in software-defined networks

As global internet traffic continues to increase, network operators face challenges on how to efficiently manage transmission in their networks. Even though attempts are underway to make optical networks automatic, the majority of actions related to traffic engineering are still performed manually by the administrators. In this paper we propose an Automatic Hidden Bypasses approach to enhance resource utilization in optical networks. Our solution uses the software-defined networking concept to automatically create or remove hidden bypasses which are not visible at the network layer. The mechanism increases throughput and reduces transmission delays

Congestion control in flow-aware networks Ph.D. thesis /

Tyt. z ekranu tytułowego.Praca doktorska. Akademia Górniczo-Hutnicza im. Stanisława Staszica (Kraków), 2009.Zawiera bibliogr. Indeks.Dostępna także w wersji drukowanej.Tryb dostępu: Internet.QoS, differentiated services model, quality of service, net neutrality, admission control operation, priority fair queuing, deficit round robin, congestion control vs. congestion avoidance, concept, new proposals, bandwidth sharing, admission, avoidance, mechanisms for FAN, algorithms, enhanced flushing, RAEF, RBAEF, RPAEF, verification of the models, simulation tool, type, technique for data collection, parameters, credibility, new methods for estimating the congestion indicators, fair rate parameter, priority load parameter, analysis, experiments on EFM, FAN in case of failure, approximate flow-aware networking, new architecture, motivation, AFAN, enqueue, dequeue operation, complexity, calculation, verification, simulation scenario in TCL cod

12 th POLISH TELETRAFFIC SYMPOSIUM PSRT2005 PSRT RECOVERY, FAIRNESS AND CONGESTION CONTROL MECHANISMS IN RPR NETWORKS

The paper describes fundamental features of RPR (Resilient Packet Ring- IEEE 802.17 standard). It focuses on proposals how to improve fairness mechanism and to increase network efficiency in state of congestion. Recovery mechanisms are also discussed, with presented analytical and simulation results. The goals of paper are threefold. At first, we show RPR main features and describe its current status. Secondly, we present main recovery and resilience features of RPR and propose solutions for improving both fairness and congestion control. Finally, a new concept, the enhanced hold-off timer (EHOT) is introduced improving recovery actions in multilayer networks. Some simulation results are presented in order to illustrate advantages of proposed solution. Index terms-Resilient Packet Ring (RPR), OTN, congestion control, fairness, resilience 1

Admission Control Policies in Flow-Aware Networks

ABSTRACT In this paper, the admission control policies proposed for Cross-Protect routers in Flow-Aware Networks (FAN) are compared. A Multilayer FAN (MFAN) architecture defines policies to decide which flows are more suitable to be transmitted through the optical layer in case of congestion. In this work, we evaluate how to include the information of such policies in the admission control process. As a result of the analysis, a new admission control strategy is proposed. This solution inherits the advantages from already established admission control proposals while ensuring fast acceptance times of new streaming flows