Journal of Satellite, Information and Communications (한국위성정보통신학회논문지)

Korea Society of Satellite Technology (한국위성정보통신학회)
권호 표지

Adaptive Congestion Control Scheme of TCP for Supporting ACM in Satellite PEP System

위성 PEP시스템에서 ACM 지원을 위한 적응형 TCP 혼잡제어기법

  • 박만규 (한국전자통신연구원 위성무선융합연구부 위성광대역방송통신연구실) ;
  • 강동배 (한국전자통신연구원 위성무선융합연구부 위성광대역방송통신연구실) ;
  • 오덕길 (한국전자통신연구원 위성무선융합연구부 위성광대역방송통신연구실)
  • Received : 2013.01.07
  • Accepted : 2013.02.25
  • Published : 2013.03.30
Download PDF
⟨ Previous Next ⟩

Abstract

Currently satellite communication systems usually use the ACM(Adaptive Coding and Modulation) to extend the link availability and to increase the bandwidth efficiency. However, when ACM system is used for satellite communications, we should carefully consider TCP congestion control to avoid network congestions. Because MODCODs in ACM are changed to make a packet more robust according to satellite wireless link conditions, bandwidth of satellite forward link is also changed. Whereas TCP has a severe problem to control the congestion window for the changed bandwidth, then packet overflow can be experienced at MAC or PHY interface buffers. This is a reason that TCP in transport layer does not recognize a change of bandwidth capability form MAC or PHY layer. To overcome this problem, we propose the adaptive congestion control scheme of TCP for supporting ACM in Satellite PEP (Performance Enhancing Proxy) systems. Simulation results by using ns-2 show that our proposed scheme can be efficiently adapted to the changed bandwidth and TCP congestion window size, and can be useful to improve TCP performance.

최근 위성 통신 시스템은 링크 가용도와 대역폭 효율을 증대시키기 위해 ACM(Adaptive Coding and Modulation) 기술을 사용하고 있지만, PEP(Performance Enhancing Proxy)에서 동작하는 TCP는 ACM 동작에 따라 변경된 물리계층 전송능력을 감지하지 못하고 작아진 BDP (Bandwidth Delay Product) 네트워크에 혼잡을 발생 시킨다. 본 논문에서는 ACM과 PEP를 사용할 때 발생되는 문제점을 극복하여 PEP의 성능을 향상시키는 기법을 제안한다. 이를 위해 ACM기능을 지원하는 물리/MAC(링크)계층 모듈과 전송계층 모듈인 TCP 간에 정보 전달 메시지를 적용하여 물리/MAC(링크)계층의 정보가 TCP에 전달되도록 하여 MODCOD (Modulation and Coding)에 따라 변경되는 물리계층 대역폭을 고려한 적응적인 TCP 혼잡제어를 수행하도록 하였다. 제안한 기법에 대해서 ns-2를 이용한 모의시험 결과 물리계층과 전송계층간의 전송 속도를 적응적으로 정합시킴으로써 네트워크의 혼잡을 미리 방지하고 최적화된 혼잡제어를 수행함으로써 PEP 성능을 향상 시킬 수 있음을 보였다.

Keywords

References

  1. Fei Peng, Lijuan Wu and Victor C. M. Leung, "Cross-layer enhancement of TCP split-connections over satellite links", International Journal of Satellite Communications and Networking, 24:405-418, 2006. https://doi.org/10.1002/sat.849
  2. Elizabeth Rendon-Morales,"Adaptive Packet Scheduling for support of QoS over DVB-S2 Satellite Systems,"9th International Conference on Wired/Wireless Internet Communications(WWIC 2011), vol.6649, pp.15-26, 2011.
  3. Mahbub Hassan, Raj Jain, "High Performance TCP/IP Networking Concepts, Issues, and Solutions", Person Prentice Hall, pp. 211-217, 2004
  4. Jeffrey C. Mogul and Steve E. Deering. Internet Engineering Task Force, "Path MTU Discovery", RFC 1191, IETF, November 1990.
  5. V. Jacobson, R. Braden, and D. Borman, "TCP extentions for high perfromance", RFC 1323, IETF, May 1992.
  6. M. Allman, S. Floyd, and C. Partridge, "Increasing TCP's initial window", RFC 3390, IETF, October 2002.
  7. S. Floyd, "TCP and explicit congestion notification", ACM Computer Communication Review, 25(5):10-23, October 1994.
  8. TCP Hybla Homepage, http://hybla.deis.unibo.it/
  9. C. P. Fu and S. C. Liew, "TCP Veno: TCP enhancement for transmission over wireless access networks," IEEE J. Sel. Areas Commun., vol. 21, no. 2, February 2003.
  10. Tom Kelly, "Scalable TCP:improving performance in highspeed wide area networks", ACM Sigcomm Computer Communication Review Vol. 33 Issue2, pp. 83-91, April 2003
  11. Luglio M., Roseti C., Savone G., Zampognaro F., "TCP Noordwijk for High-Speed Trains", SPACOMM, pp. 102-106, July 2009
  12. M.S Shin, M.K Park, D.G Oh, B.C Kim, J.Y Lee, "Practical Vertical Handover Mechanisms between Satellite and Terrestrial Networks," LNCS Vol.6294, pp 353-364, 2010.
  13. Media Independent Handover, http://www.ieee802.org/21
  14. J. Border, et al. "Performance enhancing proxies intended to mitigate link-related degradations", RFC 3132, IETF, June 2001.