Browsing by Author "Hu, SC"

Now showing 1 - 9 of 9

A FIFO-based buffer management approach for the ATM GFR services
(2000-06-01)
Chan, CT
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Hu, SC
;
Wang, PC
;
Chen, YC
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資訊工程學系
We investigate the TCP packet transmission over the ATM Guaranteed Frame Rate (GFR) service using a selective packet-discard with buffer vacancy tracking strategy and a packet-based push-out buffering scheme. Our approach is based on FIFO queueing discipline, it features fair sharing of available resources as well as feasibility in hardware implementation.
An adaptive priority traffic control approach for guaranteed services in ATM networks
(1997)
Chen, YC
;
Chan, CT
;
Hu, SC
;
資訊工程學系
;
Department of Computer Science
This paper presents an adaptive priority traffic control approach which uses a dynamic buffer allocation scheme, and an adaptive priority queuing technique for handling the delay-sensitive traffic in ATM networks. The former adjusts the buffer size based on the real traffic demand, while the latter adaptively change the priority. The simulation results show that diverse delay-sensitive traffic achieve satisfied performance through our approach. It may fulfill the emerging needs of guaranteed services.
Design and analysis of delay control for CBR services in ATM networks
(1998-05-15)
Chen, YC
;
Chan, CT
;
Hu, SC
;
資訊工程學系
;
Department of Computer Science
Asynchronous transfer mode (ATM) networks are designed to provide end-to-end transport of user data via virtual connections with specified quality of services (QOS), which is expected to be satisfied through effective traffic control mechanisms. This paper presents an adaptive delay-jitter control (ADJC) method that guarantees the delay bounds of constant bit rate (CBR) services in ATM networks. Our proposed method is based on a node-by-node time-frame scheme. Through both mathematical derivation and simulation, we have demonstrated that ADJC features a significant improvement over existing approaches in jitter delay, which can be reduced to one time-frame from end-to-end for CBR traffic. Simulation results have shown that CBR services receive satisfactory delay performance using our approach. (C) 1998 Elsevier Science B.V.
Frame-based priority scheduling in hybrid IP/ATM networks
(1999-08-25)
Chen, YC
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Hu, SC
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Chan, CT
;
Lee, CL
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資訊工程學系
The exploding growth of World Wide Web applications in recent years has overwhelmed the internet with multimedia traffic. A future performance concern is to keep pace with the quickly growing bandwidth requirements. IP over ATM is a way to relax such requirements. It provides a hybrid approach to support both layer 3 software forwarding and layer 2 ATM hardware switching. A switched virtual connection may be suitable for traffic involving large data transfers and QoS provision like Guarantee Service (GS) applications. In the hybrid IP/ATM networks, the packet-level instead of the cell-Level behavior is the relevant measure of performance. In this paper, we propose a so-called Frame-based Priority Scheduling (FBPS) algorithm far GS applications. FBPS focuses on the packet-level performance while transmitting based on cells. The most attractive feature of FBPS is its simplicity. We provide a systematic analysis of FBPS scheduler and derive the bound on its fairness when the how traffic is shaped by a leaky bucket. It shows that FBPS is competitive with certain complex scheduling disciplines such as PGPS. We also verify our analytical bounds by simulation. (C) 1999 Elsevier Science B.V. All rights reserved.
Least required bandwidth in VP-based ATM networks
(1997)
Chen, YC
;
Hu, SC
;
Chan, CT
;
資訊工程學系
;
Department of Computer Science
In an ATM network, a virtual path (VP) is a labeled path which can be used to transport a bundle of virtual connections (VCs) and to management the resources used by these connections. The ATM multimedia leased line service is provided across user-to-user VPs. Customers can increase/decrease VP bandwidth according to their demand. This paper proposes a method to derive the least required bandwidth on a VP which is the minimum amount of bandwidth estimated to satisfy the QoS requirement of VCs. The least required bandwidth can be a warranty of VP resource reallocation.
On the effective traffic control of ABR services in ATM networks
(1998-02-01)
Chen, YC
;
Chan, CT
;
Hu, SC
;
資訊工程學系
;
Department of Computer Science
Although ATM networks support various traffic requirements, but many data applications are unable to precisely specify traffic parameters such as bit rate. These applications generally require a dynamic share of the available bandwidth among all active connections, they are called available-bit-rate (ABR) service. Due to bursty and unpredictable pattern of an ABR data stream, its traffic control is more challenging than other services. In this paper, we present an improved ABR traffic control approach, called Offset Proportional Rate Control Algorithm (OPRCA). The proposed approach achieves high link utilization, low delay and weighted fair sharing among contenting sources according to the predefined OPR. The implementation is much simpler than that of existing schemes. OPRCA combines an end-to-end rate control with link-by-link feedback control, and employs a buffering scheme that avoids Head-of-Line (HOL) blocking. It can dynamically regulate the transmission rate of source traffic and maintain the real fairness among all active connections. Simulation results have shown the effectiveness of OPRCA in several performance aspects.
Routing interval: A new concept for IP lookups
(2001)
Wang, PC
;
Chan, CT
;
Hu, SC
;
Chen, YC
;
資訊工程學系
Nowadays, the commonly used table lookup scheme for IP routing is based on the so-called classless interdomain routing (CIDR). With CIDR, routers must find out the best matching prefix (BMP) for IP packets forwarding, which complicates the IP lookup. Currently, this process is mainly done in software and several schemes have been proposed for hardware implementation. Since the IP lookup performance is a major design issue for the new generation routers, in this article we investigate the properties of the routing table and present a new approach for EP lookups, our approach does not require the rule of BMP and thus significantly reduces the complexity. By applying our proposed approach, the computation cost of existing schemes can be significantly reduced. We also propose an efficient IP lookup algorithm, with which we improve the binary search on prefixes to 30 MPPS and 5,000 route updates/s under the same experiment setup with an even larger routing table.
Traffic control approaches for voice over ATM networks
(1998-12-01)
Chen, YC
;
Chan, CT
;
Hu, SC
;
Wang, PC
;
資訊工程學系
In this paper we present two traffic control approaches, a circuit emulation traffic control (CETC) and an adaptive priority traffic control (APTC) for supporting voice services in ATM networks. Most voice services can be handled as CBR traffic, this causes a lot of wasted bandwidth. Sending Voice through VBR(variable bit rate) may be a better alternative. because it allows the network to allocate voice bandwidth on demand. In CETC. the service discipline guarantees the quality of service (QOS) for voice circuits. Through mathematical analysis. we show that CETC features an adequate performance in delay-jitter. Moreover, it is feasible in implementation. We also present an APTC approach which uses a dynamic buffer allocation scheme to adjust the buffer size based on the real traffic need, as well as employs an adaptive priority queuing technique to handle various delay requirements for VER voice traffic. It provides an adequate QOS for voice circuits in addition to improving the multiplexing gain. Simulation results show that voice traffic get satisfied delay performance using our approaches. It may fulfill the emerging needs of voice service over ATM networks.
Traffic control approaches for voice over ATM networks
(1998-12-01)
Chen, YC
;
Chan, CT
;
Hu, SC
;
Wang, PC
;
資訊工程學系
In this paper we present two traffic control approaches, a circuit emulation traffic control (CETC) and an adaptive priority traffic control (APTC) for supporting voice services in ATM networks. Most voice services can be handled as CBR traffic, this causes a lot of wasted bandwidth. Sending Voice through VBR(variable bit rate) may be a better alternative. because it allows the network to allocate voice bandwidth on demand. In CETC. the service discipline guarantees the quality of service (QOS) for voice circuits. Through mathematical analysis. we show that CETC features an adequate performance in delay-jitter. Moreover, it is feasible in implementation. We also present an APTC approach which uses a dynamic buffer allocation scheme to adjust the buffer size based on the real traffic need, as well as employs an adaptive priority queuing technique to handle various delay requirements for VER voice traffic. It provides an adequate QOS for voice circuits in addition to improving the multiplexing gain. Simulation results show that voice traffic get satisfied delay performance using our approaches. It may fulfill the emerging needs of voice service over ATM networks.