This paper presents a low-cost hardware and software system that can be used to monitor ATM cell flows, and to make absolute measurements of ATM cell arrival times. The system uses a purpose-built ATM cell capture boa...
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ISBN:
(纸本)0819429910
This paper presents a low-cost hardware and software system that can be used to monitor ATM cell flows, and to make absolute measurements of ATM cell arrival times. The system uses a purpose-built ATM cell capture board in a standard LlNUX PC, with a GPS time receiver to provide an accurate time reference. The system can be used locally, or can be operated remotely, sending its results back to a central point over a network connection. As well as cell arrival times, the system computes a 32-bit signature for each cell payload. This enables the recognition of cells in different parts of the network, the measurement of cell transit time, and the detection of cell loss. Results are presented of measurements made on local and wide area ATM networks, and on the intercontinental internet.
ABT (ATM Block Transfer) is promising for effectively transferring a highly bursty data traffic in ATM networks. Most of past studies focused on the data transfer capability of ABT within the ATM layer. In actual, how...
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ISBN:
(纸本)0819429910
ABT (ATM Block Transfer) is promising for effectively transferring a highly bursty data traffic in ATM networks. Most of past studies focused on the data transfer capability of ABT within the ATM layer. In actual, however, we need to consider the upper layer transport protocol since the transport layer protocol also supports a network congestion control mechanism. One such example is TCP (Transmission control Protocol), which is now widely used in the internet. In this paper, we evaluate the performance of TCP over ABT protocols. Simulation results show that the retransmission mechanism of ABT can effectively overlay the TCP congestion control mechanism so that TCP operates in a stable fashion and works well only as an error receovery mechanism.
This Volume 3530 of the conference proceedings contains 40 papers. Topics discussed include traffic management and congestion control, cellular and wireless networking, video traffic, multicasting flow control, pollin...
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This Volume 3530 of the conference proceedings contains 40 papers. Topics discussed include traffic management and congestion control, cellular and wireless networking, video traffic, multicasting flow control, polling systems, web traffic handling, pricing and charging, capacity control and service provisioning, advances in theory, multicast networking, traffic tools and measurements and performance of internet protocols over asynchronous transfer mode networks.
Multipoint communication has been an increasingly focused topic in computer communication networks, including both the internet and the ATM networks. We have previously presented, analyzed, and evaluated new point-to-...
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ISBN:
(纸本)0819429910
Multipoint communication has been an increasingly focused topic in computer communication networks, including both the internet and the ATM networks. We have previously presented, analyzed, and evaluated new point-to-multipoint ABR flow control algorithms. In this paper, we focus on multipoint-to-point flow control. As the major objective of ABR service is to provide minimum-loss, fair service to data traffic, an effective merge-point scheme for multipoint-to-point flow control should guarantee some suitable fairness. In this paper, we first examine the "essential fairness" concept proposed by Wang and Schwartz for point-to-multipoint flow control in the internet. We extend and enhance the concept to the multipoint-to-point ABR flow control. A general algorithm guaranteeing essential fairness is presented, with a detailed implementation on top of the ERICA unicast algorithm proposed by Jain, et. al. The general algorithm may be used for a wide range of fairness specifications to accommodate various bandwidth requirement from unicast or multicast sources of different application streams. Three major variations of the general algorithm are presented. These three schemes are simulated and evaluated, and compared with an existing scheme proposed by Ren, Siu, and Suzuki. Simulation results show that the proposed merge-point algorithm achieves, within short transient time, max-min fairness based on different weights given to individual sources or sessions, or according to various specifications of fairness. The fairness concept and the general algorithm presented here may be readily applied to other high-speed networks such as the Next Generation internet and Wireless ATM, and to different multicast settings such as point-to-multipoint and multipoint-to-multipoint.
Scalable web servers can be built using a network of Workstations (NOW) where server capacity can be added by adding new workstations as the workload increases. The task of load balancing Hyper Text Transfer Protocol ...
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ISBN:
(纸本)0819429910
Scalable web servers can be built using a network of Workstations (NOW) where server capacity can be added by adding new workstations as the workload increases. The task of load balancing Hyper Text Transfer Protocol (HTTP) traffic to scalable web servers is the topic of this paper. We present a classification framework for scalable web servers, and present simulations of a clustered web server. The cluster communication is modeled using a detailed, verified model of TCP/IP processing over Asynchronous Transfer Mode (ATM). The simulator is a trace driven discrete event simulator, and the traces are obtained from the proxy server of a large internet Service Provider (ISP) in Norway. Various load balancing schemes are simulated for the prototype using remapping in the network and compared with the Rotaing Nameserver approach. We show that the Round Robin load balancing policy implemented in a modified router gives better average response time and better load balancing than the Rotating Nameserver method used in current scalable web servers.
The main problem complicating multicast video transport is variation in network bandwidth constraints. This paper presents a novel credit-based multicast flow control approach, which allows for potentially full utiliz...
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ISBN:
(纸本)0819429910
The main problem complicating multicast video transport is variation in network bandwidth constraints. This paper presents a novel credit-based multicast flow control approach, which allows for potentially full utilization of all branches in a multicast tree at the expense of low priority packets losses. It uses hop-by-hop flow control as well as explicit rate congestion feedback from the destinations. The responsiveness, bandwidth utilization, video quality and fairness of the mechanism are evaluated through simulations. Results suggest that the proposed mechanism is capable of providing a high quality video service in the presence of varying bandwidth constraints.
The Available Bit Service (ABR) is a promising "best effort" service designed to achieve in ATM networks high efficiency and low cell loss. Since the ATM Forum approved a first standard, intensive research h...
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ISBN:
(纸本)0819429910
The Available Bit Service (ABR) is a promising "best effort" service designed to achieve in ATM networks high efficiency and low cell loss. Since the ATM Forum approved a first standard, intensive research has been done about ABR. The aim of this paper is to analyse the main research topics involved in ABR, namely: the evaluation of traffic and congestion control schemes, conformance definition and policing and charging.
In this paper, we demonstrate the existence of fair end-to-end window-based congestion control protocols for packet-switched networks with FCFS routers. Our definition of fairness generalizes proportional fairness and...
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ISBN:
(纸本)0819429910
In this paper, we demonstrate the existence of fair end-to-end window-based congestion control protocols for packet-switched networks with FCFS routers. Our definition of fairness generalizes proportional fairness and includes arbitrarily close approximations of max-min fairness. The protocols use only information that is available to end hosts and are designed to converge reasonably fast. Our study is based on a multiclass fluid model of the network. The convergence of the protocols is proved using a Lyapunov function. The technical challenge is in the construction of the protocols.
We consider a dynamically reconfigurable network environment where dynamically changing traffic is offered. Rearrangement and adjustment of network capacity can be performed to maintain Quality;of Service (QoS) requir...
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ISBN:
(纸本)0819429910
We consider a dynamically reconfigurable network environment where dynamically changing traffic is offered. Rearrangement and adjustment of network capacity can be performed to maintain Quality;of Service (QoS) requirements for different traffic classes in the dynamic traffic environment. In this work, we specifically consider the case of a single, dynamic traffic class scenario in a loss mode environment. We have developed a numerical, analytical tool which models the dynamically changing network traffic environment using a time-varying, fluid-flow, differential equation that can be used to study the impact of an adaptive capacity adjustment control scheme. We present the results for a simple, blocking-based capacity adjustment, control scheme. In particular, we show that a purely blocking-based capacity adjustment control scheme can be very sensitive to capacity changes, and can lead to network instability.
This tutorial paper surveys the important issues in stability and sensitivity analysis of ABR flow control of ATM networks. The stability and sensitivity issues are formulated in a systematic framework. Four main caus...
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ISBN:
(纸本)0819429910
This tutorial paper surveys the important issues in stability and sensitivity analysis of ABR flow control of ATM networks. The stability and sensitivity issues are formulated in a systematic framework. Four main causes of instability in ABR flow control are identified: unstable control laws (the mathematical formula used for computing rates), temporal variations of available bandwidth with delayed feedback control, misbehaving components (such as misbehaving sources, misbehaving switches, mis-programmed parameters, etc.), and interactions between higher layer protocols (such as TCP) and ABR flow control. Popular rate-based ABR flow control protocols are evaluated. Stability and sensitivity is shown to be the fundamental issues when the network has dynamically-varying bandwidth. Simulation results confirming the theoretical studies are provided. Open research problems are discussed.
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