5474275
Overload based explicit rate switch schemes with MCR guarantees
An explicit rate switch scheme monitors the load at each link and gives feedback to the sources. We define the overload factor as the ratio of the input rate to the available capacity. In this paper, we present three overload-based switch schemes which provide MCR (minimum cell rate) guarantees for the ATM (asynchronous transfer mode) ABR (available bit rate) service. The switch schemes proposed use the overload factor and other terms including current source rate and target utilization to calculate feedback rates. A dynamic queue control mechanism is used to achieve efficient usage of the link, control queues and, achieve constant queuing delay at steady state. The proposed algorithms are studied and compared using several configurations. The configurations were chosen to test the performance of the algorithms in the presence of link bottlenecks, source bottlenecks and transient sources. Finally, a comparison of the proposed algorithms based on the simulation results is given.
609563
A definition of general weighted fairness and its support in explicit rate switch algorithms
We give a general definition of weighted fairness and discuss how a pricing policy can be mapped to general weighted (GW) fairness. The GW fairness can be achieved by calculating the excess fairshare (weighted fairshare of the left over bandwidth) for each VC. We show how a switch algorithm can be modified to support the GW fairness by using the excess fairshare term. We use ERICA+ as an example switch algorithm and show how it can be modified to achieve the general fairness. Simulations results are presented to demonstrate that, the modified switch algorithm achieves GW fairness. An analytical proof for convergence of the modified ERICA+ algorithm is given in the appendix.
5318665
Providing rate guarantees to TCP over the ATM GFR service
The ATM guaranteed frame rate (GFR) service is intended for best effort traffic that can benefit from minimum throughput guarantees. Edge devices connecting LANs to an ATM network can use GFR to transport multiple TCP/IP connections over a single GFR VC. These devices would typically multiplex VCs into a single FIFO queue. It has been shown that in general, FIFO queuing is not sufficient to provide rate guarantees, and per-VC queuing with scheduling is needed. We show that under conditions of low buffer allocation, it is possible to control TCP rates with FIFO queuing and buffer management. We present analysis and simulation results on controlling TCP rates by buffer management. We present a buffer management policy that provides loose rate guarantees to SACK TCP sources when the total buffer allocation is low. We study the performance of this buffer management scheme by simulation.
5623657
Satellite ATM Network Architectural Considerations and TCP/IP Performance
In this paper, we have provided a summary of the design options in Satellite-ATM technology. A satellite ATM network consists of a space segment of satellites connected by inter-satellite crosslinks, and a ground segment of the various ATM networks. A satellite-ATM interface module connects the satellite network to the ATM networks and performs various call and control functions. A network control center performs various network management and resource allocation functions. Several issues such as the ATM service model, media access protocols, and traffic management issues must be considered when designing a satellite ATM network to effectively transport Internet traffic. We have presented the buffer requirements for TCP/IP traffic over ATM-UBR for satellite latencies. Our results are based on TCP with selective acknowledgments and a per-VC buffer management policy at the switches. A buffer size of about 0.5 * RTT to 1 * RTT is sufficient to provide over 98% throughput to infinite TCP traffic for long latency networks and a large number of sources. This buffer requirement is independent of the number of sources. The fairness is high for a large numbers of sources because of the per-VC buffer management performed at the switches and the nature of TCP traffic.
3204907
Performance of Bursty World Wide Web (WWW) Sources over ABR
Bobby Vandalore, Shivkumar Kalyanaraman, Raj Jain, Rohit Goyal, Sonia Fahmy The Ohio State University, Department of CIS Columbus, OH 43210-1277 Phone: 614-688-4482, Fax: 614-292-2911 Email: fvandalor, shivkuma, jain, goyal, fahmyg@cis.ohio-state.edu Seong-Cheol Kim Principal Engineer, Network Research Group, Communication Systems R&D Center Samsung Electronics Co. Ltd., Chung-Ang Newspaper Bldg. 8-2, Karak-Dong, Songpa-Ku, Seoul, Korea 138-160 Email: kimsc@metro.telecom.samsung.co.kr Abstract
16677800
AQuaFWiN: adaptive QoS framework for multimedia in wireless networks and its comparison with other QoS frameworks
In a wireless environment, due to topology changes and characteristics of media (interference in radio signals) the bandwidth of a link is unpredictable and possibly very low, the error rates are variable and extremely high. Provisioning and guaranteeing quality of service (QoS) in such an environment is a very challenging problem. In this paper we propose an adaptive and QoS framework to support multimedia applications in a wireless networking environment. The proposed framework is hierarchical in nature with cluster of mobile end hosts connected to a base station, base stations are connected to a supervisory node, which in turn is connected to the wired infrastructure. The changing conditions in wireless due to interference and possibly mobility, entitle that the real-time applications needing stringent QoS should be adaptable. The framework uses a generic feedback mechanism to support adaptability at all layers of the wireless network. An overview of existing wireless architectures which support QoS is given. The architectures discussed are WAMIS (wireless adaptive multimedia information system), SWAN (seamless wireless ATM network), MMWN (multimedia support for mobile wireless networks), and QGMC (QoS guarantees in mobile computing). The proposed approach is compared with these existing methods.
206477429
Mobile Multimedia
38848848
Rough Set Based Decision Tree Model for Classification
Decision tree, a commonly used classification model, is constructed recursively following a top down approach (from the general concepts to particular examples) by repeatedly splitting the training data set. ID3 is a greedy algorithm that considers one attribute at a time for splitting at a node. In C4.5, all attributes, barring the nominal attributes used at the parent nodes, are retained for further computation. This leads to extra overheads of memory and computational efforts. Rough Set theory (RS) simplifies the search for dominant attributes in the information systems. In this paper, Rough set based Decision Tree (RDT) model combining the RS tools with classical DT capabilities, is proposed to address the issue of computational overheads. The experiments compare the performance of RDT with RS approach and ID3 algorithm. The performance of RDT over RS approach is observed better in accuracy and rule complexity while RDT and ID3 are comparable.
39032710
Refining decision tree classifiers using rough set tools
The proposed hybridized rough set framework is composed of traditional Rough Set (RS) approach and classical Decision Tree (DT) induction algorithm. RS helps to identify dominant attributes and DT algorithm results in simpler and generalized classifier. The implementation of the Hybridized Rough Set Framework is presented as the RDT algorithm. GA heuristics are used to generalize the RDT algorithm further. Experimental results obtained on applying the hybridized rough set framework and the related base algorithms on datasets belonging to the three categories are presented in this paper. Accuracy, complexity, number of rules and number of attributes in the induced classifier assess the performance of the candidate algorithms. The results indicate that the proposed framework is an effective model for classification.
15984449
Visual information retrieval
New updated! The latest book from a very famous author finally comes out. Book of visual information retrieval, as an amazing reference becomes what you need to get. What's for is this book? Are you still thinking for what the book is? Well, this is what you probably will get. You should have made proper choices for your better life. Book, as a source that may involve the facts, opinion, literature, religion, and many others are the great friends to join with.
7565598
Towards coarse-grained mobile QoS
Supporting Quality of Service is an important objective for future mobile and wireless systems, and requires resource reservation and admission control to achieve. In this paper, we introduce a novel coarse grained approach to admission control termed Virtual Bottleneck Cell. Our approach is designed to scale to many users and handoffs, while simultaneously controlling “hot spots” and system bottlenecks. The key technique is to hierarchically control the virtual system, ensuring QoS objectives are satisfied without requiring models or accurate predictions of the users’ future locations. We develop a simple analytical model to study the system and illustrate several key components of the approach. Finally, we perform simulations in a two-dimensional network to compare the performance obtained with Virtual Bottleneck Cell with alternate schemes, including the optimal off line algorithm.