Browsing by Author "Lai, KC"

Now showing 1 - 4 of 4

A fast computation algorithm for connection admission control of delay sensitive traffic with multiple quality of service requirements
(1996-08-01)
Lee, TH
;
Lai, KC
;
交大名義發表
;
電子工程學系及電子研究所
;
National Chiao Tung University
This paper presents a fast computation algorithm for connection admission control for heterogeneous delay sensitive traffic in ATM networks. Cell loss probability is adopted as the measure of quality of service. In our study, cells of each connection are allowed to have two different loss priorities and the aggregate traffic can have more than two. To cope with multiple quality of service requirements, the link capacity is divided into several bands. For simplicity, each traffic source is assumed to alternate between active and idle periods. However, the results can be extended to traffic sources having more than two states. Upper bounds of actual cell loss probabilities are derived based on the bufferless fluid flow model. Numerical results show that the upper bounds are close to the actual cell loss probabilities.
Characterization of delay-sensitive traffic
(1998-08-01)
Lee, TH
;
Lai, KC
;
電信工程研究所
;
電信研究中心
;
Institute of Communications Engineering
Resource allocation is necessary for a network which guarantees quality of service (QoS), In this paper we first present a definition for a traffic stream to be burstier than another traffic stream. The definition is based on the loss probability of a bufferless multiplexer and thus is appropriate for delay-sensitive traffic which cannot tolerate queueing delay caused by buffering. An optimum quantization algorithm is then derived for source characterization. The optimally quantized version achieves minimum loss rate for all possible allocated bandwidths under the condition that it is burstier than the real traffic. The quantized source is called a pseudosource and can be used by the network for resource allocation. Some numerical examples are studied. Results show that, for a bufferless multiplexer, the allocated bandwidth based on optimally quantized pseudosources is only slightly greater than the minimum bandwidth required to meet the requested QoS.
Design of a real-time call admission controller for ATM networks
(1996-10-01)
Lee, TH
;
Lai, KC
;
Duann, ST
;
電子工程學系及電子研究所
;
電信工程研究所
In this paper, we present a real-time computation algorithm based on the bufferless fluid flow model [6] for call admission control (CAC) on one link of an asynchronous transfer mode (ATM) network with heterogeneous bursty traffic, Cell loss probability is adopted as the measure of quality-of-service (QoS), Our computation algorithm requires a constant memory size and needs only two multiplications and one division to determine whether a connection request can be accepted or not. It is known [7], that due to the interference between different types of traffic the individual cell loss probability may not meet the requirement even though the global one does, In this paper, we provide a close upper-bound for individual cell loss probability which can easily be obtained with our computation algorithm, Numerical examples using typical traffic parameters are studied to corroborate the upper-bound, We also compare the performance of the investigated CAC scheme with that of the effective bandwidth technique [9].
Estimates of loss probabilities for delay-sensitive traffic in ATM networks
(1996-06-20)
Lai, KC
;
Lee, TH
;
傳播研究所
;
電控工程研究所
;
Institute of Communication Studies
Simple estimates of loss probabilities for heterogeneous delay-sensitive traffic in ATM networks are presented. Cells of different connections can have different loss priorities. Numerical results show that the estimates, which are derived from the bufferless fluid flow model, are close to the actual cell loss probabilities.