An Analysis of Alterations to the SCTP RTO Calculation Mechanism for WLAN Environments

  • Sheila Fallon
  • Paul Jacob
  • Yuansong Qiao
  • Liam Murphy
  • Enda Fallon
  • Austin Hanley
Part of the IFIP International Federation for Information Processing book series (IFIPAICT, volume 284)

As a connection oriented transport layer protocol the Stream Control Transmission Protocol (SCTP) inherits many of the features of the Transmission Control Protocol (TCP) including the mechanism by which Retransmission Timeout (RTO) is calculated. Previous investigations have established that the mechanism through which SCTP calculates RTO is inappropriate in Wireless LAN (WLAN) environments. This paper investigates the performance implications of changes to the SCTP RTO calculation mechanism. In particular alterations to the parameters α, the smoothing factor, and β, the delay variance factor are investigated. Results indicate that performance improvements are achievable through careful selection of α and β values. Throughput improvements of 63% over the default mechanism defined in RFC 4960 are described. These performance improvements however, while significant, still can not address the switchover delays which result from the distortions caused by continuously increasing RTT values in WLAN environments.


Mobile Node Transmission Control Protocol Primary Path Stream Control Transmission Protocol Data Chunk 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


  1. 1.
    R. Stewart et al. Stream Control Transmission Protocol, RFC 4960, Sep. 2007.Google Scholar
  2. 2.
    Fallon, S et al. A “SCTP Switchover Performance Issues in WLAN Environments”, IEEE Consumer Communications & Networking Conference (CCNC) 2008Google Scholar
  3. 3.
    Allman, M., Paxson V. “Computing TCP's Retransmission Timer” RFC 2988 November 2000Google Scholar
  4. 4.
    Jacobson, V., "Congestion Avoidance and Control", Computer Communication Review, vol. 18, no. 4, pp. 314-329, Aug.Google Scholar
  5. 5.
    Braden, R., "Requirements for Internet Hosts - Communication Layers", RFC 1122, October 1989.Google Scholar
  6. 6.
    Karn, P. and C. Partridge, "Improving Round-Trip Time Estimates in Reliable Transport Protocols", SIGCOMM 87.Google Scholar
  7. 7.
    Jacobson V.Braden R. Borman. D “TCP Extensions for High Performance” May 1992Google Scholar
  8. 8.
    Allman, M., Paxson V. and W. Stevens, "TCP Congestion Control", RFC 2581, April 1999.Google Scholar
  9. 9.
    Kesselman, A, Mansourz, Y, “Optimizing TCP Retransmission Timeout”, 4th International Conference on Networking, Reunion Island, France 2005Google Scholar
  10. 10.
    Scharf, M, Necker, M, Gloss, B, “The Sensitivity of TCP to Sudden Delay Variations in Mobile Networks” Lectute notes in Computer Science 2004Google Scholar
  11. 11.
    Gurtov, A, “Effect of Delays on TCP Performance” IFIP Personal Wireless Communications 2001, Lappeenranta, FinlandGoogle Scholar
  12. 12.
    Huang, H, Cai, J, “Improving TCP performance during soft vertical handoff”, 19th International Conference on Advanced Information Networking and Applications, 2005.Google Scholar
  13. 13.
    Fu, S, Atiquzzaman, M, Ivancic, W, “Effect of delay spike on SCTP, TCP Reno, and Eifel in a wireless mobile environment” Conference on Computer Communications and Networks, 2002.Google Scholar
  14. 14.
    Budzisz L et al. “An Analytical Estimation of the Failover Time in SCTP Multihoming Scenarios” Wireless Communications and Networking Conference (WCNC) 2007Google Scholar
  15. 15.
    Qiao Y et al. “SCTP Performance Issue on Path Delay Differential”, Wired/Wireless Internet Communications (WWIC) 2007Google Scholar
  16. 16.
    Kelly, A, et al. “Delay-Centric Handover in SCTP over WLAN”, Transactions on Automatic Control and Computer Science, 49, 63 (2004), 1--6.Google Scholar
  17. 17.
    Min-Chin, C, Jen-Yi, P, Ting-Wei, H, ”A Smart Path Failure Detection Method for SCTP in Wireless Network” International Conference on Wireless Communications, Networking and Mobile Computing, 2007. WiCom 2007.Google Scholar
  18. 18.
    Kim, D, Koh, S, Kim, Y, “A Scheme of Primary Path Switching for Mobile Terminals Using SCTP Handover” 2007 annual Conference on International Conference on Computer Engineering and ApplicationsGoogle Scholar
  19. 19.
    IXChariot Console version 6.50
  20. 20.
    A. Caro, et al : ns-2 SCTP module, Version 3.5,
  21. 21.
    G. Combs, et al : Wireshark network protocol Analyzer, Version 0.99.5,

Copyright information

© International Federation for Information Processing 2008

Authors and Affiliations

  • Sheila Fallon
    • 1
  • Paul Jacob
    • 1
  • Yuansong Qiao
    • 1
  • Liam Murphy
    • 2
  • Enda Fallon
    • 1
  • Austin Hanley
    • 1
  1. 1.Software Research CentreAthlone Institute of TechnologyIreland
  2. 2.Performance Engineering LaboratoryUniversity College DublinIreland

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