IEEE International Communications Conference (ICC), May 2003.
Abstract: We study the performance of TCP over a satellite link,
which is subject to intermittent blockages. Our simulation-based study
characterizes the performance degradation of transferring messages ranging
from small web objects to large files over satellite channels with widely
varying blockage statistics. Using a split connection gateway, we investigate
the impact of trying to preserve TCP end-to-end semantics upon connection
close and find that such an approach significantly reduces the ability of
small TCP transfers to survive a long duration blockage. We show
that by tying the satellite gateway's offered window to the terrestrial TCP
sender to the space in the send buffer on the satellite side, and by quickly
responding when the satellite link becomes available, the split-connection
gateway can essentially eliminate the delay incurred waiting for the TCP
persist timer to expire. Finally, we illustrate how aspects of the
gateway's design affect large and small TCP transfers differently.