Multiplex communications – Pathfinding or routing – Switching a message which includes an address header
Reexamination Certificate
2011-03-15
2011-03-15
Phunkulh, Bob A (Department: 2477)
Multiplex communications
Pathfinding or routing
Switching a message which includes an address header
C714S748000
Reexamination Certificate
active
07907613
ABSTRACT:
Round-trip time estimates may be calculated from an acknowledgement of an original packet transmission or from an acknowledgment of a retransmission without ambiguity by using different segment sizes for the same packet during transmission and retransmission. By using different segment sizes, the retransmitted segment will be acknowledged with a different acknowledgement number. In one embodiment, a TCP sender uses segment sizes that are slightly smaller than the maximum segment size for the initial transmission (e.g. MSS-4 bytes), and uses maximally sized segments during retransmission. When one of the two transmissions is explicitly acknowledged, the TCP sender can then use the different byte sequence acknowledgement numbers to discern which transmission is being acknowledged and correctly measure the round-trip time. This also allows the TCP sender to initiate the NewReno fast recovery algorithm only upon receipt of a retransmission acknowledgment. This is especially useful, for example, during periods of rapidly increasing delays caused by deteriorating network conditions or increased congestion.
REFERENCES:
patent: 5307351 (1994-04-01), Webster
patent: 6694471 (2004-02-01), Sharp
patent: 6862628 (2005-03-01), Moore et al.
patent: 2003/0023746 (2003-01-01), Loguinov
Internet Engineering Task Force (IETF) Request for Comments (RFC) 793, Transmission Control Protocol, J. Postel, Sep. 1981.
IETF RFC 1323, TCP Extensions for High Performance, V. Jacobson, et al., May 1992.
IETF RFC 2018, TCP Selective Acknowledgement Options, M. Mathis, et al., Oct. 1996.
IETF RFC 2581, TCP Congestion Control, M. Allman, et al., Apr. 1999.
IETF RFC 2582, The NewReno Modification to TCP's Fast Recovery Algorithm, S. Floyd, et al., Apr. 1999.
IETF RFC 2883, An Extension to the Selective Acknowledgement (SACK) Option for TCP, S. Floyd, et al., Jul. 2000.
IETF RFC 2988, Computing TCP's Retransmission Timer, V. Paxson, et al., Nov. 2000.
IETF RFC 3042, Enhancing TCP's Loss Recovery Using Limited Transmit, M. Allman, et al., Jan. 2001.
[Karn 87], Improving Round-Trip Time Estimates in Reliable Transport Protocols, P. Karn, et al., Computer Communication Review, vol. 17, No. 5, pp. 2-7, Aug. 1987.
Anderson Gorecki & Manaras LLP
Avaya Inc.
Phunkulh Bob A
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