TCP Performance in the Presence of Congestion and Corruption Losses

Andrei Gurtov

Master's Thesis, University of Helsinki, Department of Computer Science, Helsinki, December 2000

[Full Text in PDF Format, 732KB]


The wireless environment of slow and lossy links presents a challenge for efficient data transport. We have performed an experimental evaluation of TCP in an emulated wireless environment. We consider a network model including a lossy wireless link and a lasthop router with a limited-size buffer. We have explored how well the state-of-art TCP perform, identified key reasons behind the behavior, and measured the effect of different optimizations. We experimented with TCP connections with different values of the initial window, receiver window, with or without SACK and New Reno over the emulated network with different error rates and buffer sizes. The experimental data is obtained with a state-of-art TCP implementation of the Linux operating system and a real-time network emulator Seawind. Our main result is a comparative study and analysis of different TCP optimizations.