Abstract
We analyze two alternative retransmission timers for the Transmission Control Protocol (TCP). We first study the retransmission timer of TCP-Lite which is considered to be the current de facto standard for TCP implementations. After revealing four major problems of TCP-Lite's retransmission timer, we propose a new timer, named the Eifel retransmission timer, that eliminates these. The strength of our work lies in its hybrid analysis methodology. We develop models of both retransmission timers for the class of network-limited TCP bulk data transfers in steady state. Using those models, we predict the problems of TCP-Lite's retransmission timer and develop the Eifel retransmission timer. We then validate our model-based analysis through measurements in a real network that yield the same results.
- {1} M. Allman, V. Paxson, W. Stevens, TCP Congestion Control, RFC 2581, April 1999. Google ScholarDigital Library
- {2} M. Allman, V. Paxson, On Estimating End-to-End Network Path Properties, In Proceedings of ACM SIGCOMM 99. Google ScholarDigital Library
- {3} R. Braden, Requirements for Internet Hosts - Communication Layers, RFC 1122, October 1989.Google Scholar
- {4} L. S. Brakmo, L. L. Peterson, Performance Problems in BSD4.4 TCP, ACM Computer Communication Review, 25(5), October 1995. Google ScholarDigital Library
- {5} L. S. Brakmo, L. L. Peterson, TCP Vegas: End to End Congestion Avoidance on a Global Internet. IEEE Journal of Selected Areas in Communication, Vol. 13, No. 8, October 1995. Google ScholarDigital Library
- {6} V. Jacobson, M. J. Karels, Congestion Avoidance and Control, Revised version of a paper that appeared in Proceedings of ACM SIGCOMM 88, available at http://ee.lbl.gov/, 1992. Google ScholarDigital Library
- {7} V. Jacobson, C. Leres, S. McCanne, tcpdump, available at http://ee.lbl.gov/.Google Scholar
- {8} V. Jacobson, Modified TCP Congestion Avoidance Algorithm, Email to the end2end-interest mailing list, April 30, 1990, available at ftp://ftp.ee.lbl.gov/ email/vanj.90apr30.txt.Google Scholar
- {9} V. Jacobson, C. Leres, S. McCanne, tcpdump, available at http://ee.lbl.gov/.Google Scholar
- {10} V. Jacobson, R. Braden, D. Borman, TCP Extensions for High Performance, RFC 1323, May 1992.Google Scholar
- {11} P. Karn, C. Partridge, Improving Round-Trip Time Estimates in Reliable Transport Protocols, In Proceedings of ACM SIGCOMM 87. Google ScholarDigital Library
- {12} R. Ludwig, A Case for Flow-Adaptive Wireless Links, Technical Report UCB//CSD-99-1053, University of California at Berkeley, May 1999. Google ScholarDigital Library
- {13} R. Ludwig, R. H. Katz, The Eifel Algorithm: Making TCP Robust Against Spurious Retransmissions, ACM Computer Communication Review, 30(1), January 2000. Google ScholarDigital Library
- {14} R. Ludwig, Model of the TCP Sender Connection State in Equilibrium, available at http://iceberg.cs.berkeley.edu, January 1999.Google Scholar
- {15} R. Ludwig, TCP-Eifel, Patches for FreeBSD, available at http://iceberg.cs.berkeley.edu, October 1999.Google Scholar
- {16} M. Mathis, J. Semke, J. Mahdavi, T. Ott, The Macroscopic Behavior of the TCP Congestion Avoidance Algorithm, ACM Computer Communications Review, 27(3), July 1997. Google ScholarDigital Library
- {17} S. McCanne, V. Jacobson, The BSD Packet Filter: A New Architecture for User-Level Packet Capture, In Proceedings of the 1993 Winter USENIX Conference. Google ScholarDigital Library
- {18} V. Paxson, Measurements and Analysis of End-to-End Internet Dynamics, Ph. D. dissertation, University of California, Berkeley, April 1997. Google ScholarDigital Library
- {19} J. Postel, Internet Protocol, RFC 791, September 1981.Google Scholar
- {20} J. Postel, Transmission Control Protocol, RFC793, September 1981.Google Scholar
- {21} K. K. Ramakrishnan, S. Floyd, A Proposal to add Explicit Congestion Notification (ECN) to IP, RFC 2481, January 1999. Google ScholarDigital Library
- {22} W. Simpson, The Point-to-Point Protocol, RFC 1661, July 1994.Google Scholar
- {23} W. R. Stevens, TCP/IP Illustrated, Volume 1 (The Protocols), Addison Wesley, November 1994. Google ScholarDigital Library
- {24} G. R. Wright, W. R. Stevens, TCP/IP Illustrated, Volume 2 (The Implementation), Addison Wesley, January 1995. Google ScholarDigital Library
Index Terms
- The Eifel retransmission timer
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