Evaluating the Eifel Algorithm for TCP in a GPRS network
Andrei Gurtov
Reiner Ludwig
In Proceedings of European Wireless, February 2002, Florence, Italy. (Invited paper).
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Abstract
Large and sudden variations in packet transmission delays are often 
unavoidable in GPRS. This may cause spurious timeouts in TCP. Spurious 
timeouts affect TCP performance in two ways: (1) the TCP sender 
unnecessarily reduces its load, and (2) the TCP sender is forced into a 
go-back-N retransmission mode. The Eifel algorithm avoids these 
consequences. We evaluate the performance of the Eifel algorithm for TCP 
Reno, NewReno and SACK in a simulated GPRS network. We use throughput and 
goodput as equally important performance metrics. In all our simulations, 
we find that the Eifel algorithm improves goodput; in some cases by up to 
20 percent. When complemented with an efficient loss recovery scheme (SACK 
or NewReno), we find that the Eifel algorithm also improves bulk data 
download times in all our simulations; in some cases by up to 12 percent.