Browsing by Subject "sterowanie dostępem"

Now showing 1 - 2 of 2

Access status: Open Access ,
Congestion control in flow-aware networks
(2007-05-31) (Data obrony: 2009-06-29) Domżał, Jerzy
Wydział Elektrotechniki, Automatyki, Informatyki i Elektroniki
The congestion control mechanisms for Flow-Aware Networks are presented in the dissertation. The research was performed for four proposals, the EFM (Enhanced Flushing Mechanism), the RAEF (Remove Active Elastic Flows), the RBAEF (Remove and Block Active Elastic Flows) and the RPAEF (Remove and Prioritize in access Active Elastic Flows) mechanisms. The idea of all presented congestion control mechanisms is similar and relies on total or partial cleaning of the PFL (Protected Flow List) content in the MBAC (Measurement Based Admission Control) block in congestion. The main goal of the proposed solutions is to minimize the acceptance time of new streaming flows in FAN routers. The streaming transmission in FAN is proposed for low traffic consuming applications with demands on low packet delays and loss. The congestion control mechanisms for FAN, proposed in the dissertation are described in details and analyzed by simulation experiments run on the ns-2 simulator. The obtained results show the advantages of the new solutions. The second part of the dissertation presents the new proposal of realizing the FAN concept. In this solution, the algorithm for random dropping of packets from the queue in congestion is used. It is implemented based on the AFD(Approximate Fair Dropping) mechanism. The new proposal is less complex than two well known FAN versions.
Access status: Open Access ,
Net neutral quality of service differentiation in flow-aware networks
(2008-09-25) (Data obrony: 2011) Wójcik, Robert
Wydział Elektrotechniki, Automatyki, Informatyki i Elektroniki
Flow-Aware Networking (FAN) architecture is evaluated in this dissertation with regard to its service differentiation and quality of service (QoS) assurance capabilities. The network neutrality debate is presented first, and it is shown that the potential resolutions will have a strong impact on QoS architectures. Secondly, the detailed concept of FAN is presented and compared with other flow-based QoS architectures designed for IP networks. It is argued that all the solutions have their advantages and disadvantages, however, in FAN, the pros outnumber the cons in comparison with other architectures. The main goal of the dissertation is to propose and evaluate new mechanisms to enhance service differentiation capabilities of FAN architecture. The waiting times phenomenon as a result of admission control functionality is documented. Next, differentiated blocking and differentiated queuing mechanisms are proposed. Finally, Class of Service on Demand is shown as the ultimate method of providing rich service differentiation without violating the network neutrality principle. The static limitation and automatic intelligent limitation mechanisms are proposed as a simple, yet efficient way of improving service assurance. It is shown that limitation mechanisms significantly contributes to FAN's scalability and yields great performance benefits. Finally, the predictive approach is presented, which changes the functioning of the admission control block in FAN. Instead of waiting for congestion to appear and only then blocking new connections, the mechanism takes a pro-active approach and starts to act on the basis of the predicted values of the congestion indicators.