A new scheme of combining advanced packet discard and dynamic bandwidth allocation for low delay/low jitter realtime communication using CBQ/ALTQ

S. Nakamura, N. Kato, K. Ohta, Y. Nemoto

Research output: Contribution to journalArticlepeer-review

Abstract

Recently, demand on class-of-service (CoS) has known a great increase thanks to a set of real-time applications such as Internet Telephony service. Class-Based Queuing (CBQ) is considered as an efficient queuing mechanism to guarantee CoS. ALTQ is a widely used platform for realizing CBQ. In this paper, we verify through experiments that bandwidth control of CBQ/ALTQ contains overhead for fluctuating traffic. To avoid such an overhead, we introduce dynamic bandwidth allocation scheme for real-time traffic fluctuating within fixed ranges. In the light of the limited network resources, it quickly becomes obvious that when the traffic rate exceeds the maximum available bandwidth, arriving packets will be accumulated in the router queue. As a result, the traffic delay increases and the quality of real-time applications is degraded. To cope with such a problem, we revise the RED algorithm for a large amount of traffic and propose a new packet discard algorithm that uses bandwidth as a trigger. Experiment results show that our proposal outperforms the already existing packet discard algorithms (RED, DropTail) in providing lower delay/jitter services. We show the efficiency of our proposal using a real system.

Original languageEnglish
Pages (from-to)3124-3132
Number of pages9
JournalIEICE Transactions on Communications
VolumeE84-B
Issue number12
Publication statusPublished - 2001 Dec

Keywords

  • Bandwidth allocation
  • CBQ
  • CoS
  • RED

ASJC Scopus subject areas

  • Software
  • Computer Networks and Communications
  • Electrical and Electronic Engineering

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