A Weighted Fair Packet Scheduling Method Allowing Packet Loss

패킷 손실을 허용하는 가중치 기반 공정 패킷 스케줄링

  • 김태준 (공주대학교 정보통신공학부)
  • Received : 2010.06.30
  • Accepted : 2010.08.24
  • Published : 2010.09.30

Abstract

WFQ (Weighted Fair Queuing) provides not only fairness among traffic flows in using bandwidth but also guarantees the Quality of Service (QoS) that individual flow requires, which is why it has been applied to the resource reservation protocol (RSVP)-capable router. The RSVP allocates an enough resource to satisfy both the rate and end-to-end delay requirements of the flow in condition of no packet loss, and the WFQ guarantees those QoS requirements with the allocated resource. In a practice, however, most QoS-guaranteed services, specially the Voice of IP, allow a few percent of packet loss, so it is strongly desired that the RSVP and WFQ make the best use of this allowable packet loss. This paper enhances the WFQ to allow packet loss and investigates its performance. The performance evaluation showed that allowing the packet loss of 0.4% can improve the flow admission capability by around 40 percent.

대표적 가중치 기반 공정 패킷 스케줄링 방식인 WFQ(weighted Fair Queuing)는 자원의 공정한 배분과 더불어 개별 트래픽 흐름이 요구하는 품질을 보장할 수 있어 RSVP(resource reservation protocol) 라우터에 널리 이용되어 왔다. RSVP는 패킷의 손실 없이 트래픽 흐름의 요구속도와 종단간 지연한계를 보장할 수 있는 자원을 예약하고, WFQ 스케줄러는 예약된 자원을 이용하여 흐름의 품질보장을 실현한다. 그러나 품질 보장형 서비스라 하더라도 실제적으로 몇 %까지의 패킷 손실이 허용된다. 따라서 패킷 손실을 허용하도록 RSVP와 WFQ를 개선할 필요가 있다. 본 연구에서는 패킷 손실을 허용하는 WFQ 방식에 대해 연구하고, 그의 성능을 평가한다. 성능평가 결과 0.4%의 패킷 손실을 허용할 경우 40% 정도의 흐름 수용 능력이 개선되는 효과를 관찰하였다.

Keywords

References

  1. X. Xiao and L. M. Ni, "Internet QoS: A Big Picture," IEEE Network, Vol.13, No.2, pp.8-18, 1999. https://doi.org/10.1109/65.768484
  2. A. K. Parekh and R. G. Gallager, "A generalized processor sharing approach to flow control in integrated services networks: the single node case," IEEE/ACM Transactions on Networking, Vol.3, No.1, pp.344-357, 1993.
  3. D. Ferrari and D. Verma, "A scheme for real-time channel establishment in wide-area networks," IEEE Journal of Selected Areas in Communications, Vol.8, No.3, pp.368-379, 1990. https://doi.org/10.1109/49.53013
  4. V. Sivaraman, F. M. Chiussi and M. Gerla, "Traffic shaping for end-to-end delay guarantees with EDF scheduling," Proc. IWQOS, pp. 10-18, 2000.
  5. Young-Jin Choi, Hyung-Myung Kim," A new scheduling scheme for high-speed packet networks: EarUest-wrtual-deadlme-first," Computer Communications, Vol.30, pp.2291- 2300, 2007. https://doi.org/10.1016/j.comcom.2007.06.003
  6. A. Demers, S. Keshav, and S. Shenker, "Design and analysis of a fair queuing algorithm," Proc. ACM SIGCOMM, pp. 1-12, 1989.
  7. M. Baldi and F. Risso, "Efficiency of Packet Voice with Deterministic Delay," IEEE Comm. Mag, pp. 170-177, 2000.
  8. Do-Sung Jun, Jinwoo Choe and Alberto Leon-Garcia, "Credit-based Processor Sharing for Decoupled Delay and Bandwidth Allocation", IEEE Comm. Letters, Vol.5, No. 4, pp. 178-180, 2001. https://doi.org/10.1109/4234.917106
  9. Jens Schmitt, "Optimal Network Service Curves under Bandwidth-Delay Decoupling," IEE Electronics Letters, Vol.38, No.6, pp.297-299, 2002. https://doi.org/10.1049/el:20020204
  10. Mong-Fong Homg, Wei-Tsong Lee, Kuan-Rong Lee and Yau-Hwang Kuo, "An adaptive approach to weighted fair queue with QoS enhanced on IP network," Proc. TENCON, Vol.1, pp181-186, 2001.
  11. Lijun Wang, D. Fayek and T. Sivananthan, "A Bandwidth Bargain Model based on Adaptive Weighted Fair Queueing," Proc. NOMS, pp1-4, 2006.
  12. Y. Wang, L. Fan, D. He and R. Tafazolli, "Solution to weight-adaptive fair queuing," Electronics Letters, Vol. 44, No. 5, pp. 385-387, 2008. https://doi.org/10.1049/el:20083333
  13. 인터넷전화 서비스 정책 시행계획, 정보통신부, 2004. 10.
  14. 배성룡, "E-모델 기반 통화품질 분석을 통한 VoIP Planning 및 평가," 박사학위논문, 경기대학교 대학원, 2004.
  15. Chen-Nee Chuah and Randy H. Katz, "Characterizing packet audio streams from Internet multimedia applications," Proc. ICC, Vol.2, pp. 1199-1203, 2002.
  16. Hassan HASSAN and Jean-Marie GARCIA and Olivier BRUN, "GENERIC MODELING OF MULTIMEDIA TRAFFIC SOURCES," Proc. HET-NETs, pp. 14/1-14/10, 2005.
  17. M. H. MacDougall, Simulating Computer Systems, Techniques and Tools, MIT Press, 1987.