Making TCP Robust Against Delay Spikes
University of Helsinki, Department of Computer Science, Series of Publications C, No C-2001-53, November 2001.
[Full Text in PDF Format, 88KB]
This document discusses optimizations for a TCP sender that are
most helpful in the presence
of delays spikes, but are seemingly suitable for general
deployment. The motivation for this work is
increasing popularity of links (e.g. provided by cellular
networks) that have delay spikes exceeding
the usual link latency by several times. The effect of a delay
spike on TCP Tahoe, Reno, NewReno
and SACK is described. The document recommends timing every
segment and restarting the retransmit
timer to achieve a more conservative RTO estimate. Furthermore,
it discusses how a series of
DUPACKs should be treated.