Shifting-Level Process에 기반한 영상트래픽 모델 (1부: 모델링과 대기체계 영향 분석)

A Video Traffic Model based on the Shifting-Level Process (Part I : Modeling and the Effects of SRD and LRD on Queueing Behavior)

  • 안희준 (한국과학기술원 전기및전자공학과 영상통신 연구실 정회원) ;
  • 강상혁 (서울시립대 정보전자공학부 정회원) ;
  • 김재균 (한국과학기술원 전기및전자공학과 영상통신 연구실 정회원)
  • 발행 : 1999.10.01

초록

본 논문에서는‘shifting-level (SL) process’을 기초로 한 모델을 사용하여, VBR 부호화된 영상트래픽의 long-range dependence (LRD) 특성이 대기체계에 미치는 영향에 대해서 연구하였다. 연구 내용은 제1부와 제2부로 나누어 전개된다. 제 1부에서는 실제 영상트래픽의 자기상관함수가 exponential과 hyperbolic의 복합함수로 매우 정확히 표현될 수 있음을 보이고, 이러한 조건을 만족하는 SL process with compound correlations(SLCC)를 제안한다. 대표적인 SRD 모델인 DAR(1)모델과의 대기성능 비교를 통하여 hyperbolic한 상관도가 대기체계에 끼치는 영향을 분석한다. 분석결과 영상의 LRD 특성이 대기체계에 끼치는 영향의 중요도는 단순히‘Yes/No’로 답할 수 없으며, 트래픽 부하가 높아지면 그 영향이 강하게 나타나고, 반대로 트래픽 부하가 낮은 경우에는 무시할 수 있을 정도로 약하게 나타남을 알 수 있다. 여기에 사용하는 SL/D/1/K 대기체계의 해석방법을 제2부에서 다루게 된다.

In this paper, we study the effects of long-range dependence (LRD) in VBR video traffic on queueing system. This paper consists of Part I and II. In Part I, we present a (LRD) video traffic model based on the shifting-level (SL) process. We observe that the ACF of an empirical video trace is accurately captured by the shifting-level process with compound correlation (SLCC): an exponential function in short range and a hyperbolic function in long range. We present an accurate parameter matching algorithm for video traffic. In the Part II, we offer the queueing analysis of SL/D/1/K called ‘quantization reduction method’. Comparing the queueing performances of the DAR(1) model and the SLCC with that of a real video trace, we identify the effects of SRD and LRD in VBR video traffic on queueing performance. Simulation results show that Markoivian models can estimate network performances fairly accurately under a moderate traffic load and buffer condition, whereas LRD may have a significant effect on queueing behavior under a heavy traffic load and large buffer condition.

키워드

참고문헌

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