TCP/IP Illustrated, Volume 1: The Protocols, 2nd Edition

14. TCP Timeout and Retransmission

14.1. Introduction

Efficiency and performance are issues that we have not discussed much so far. We have primarily been concerned with correctness of operation. In this chapter and the next two, we will be focusing not only on the basic tasks TCP performs, but also on how well it performs them. The TCP protocol provides a reliable data delivery service between two applications using an underlying network layer (IP) that may lose, duplicate, or reorder packets. In order to provide an error-free exchange of data, TCP resends data it believes has been lost. To decide what data it needs to resend, TCP depends on a continuous flow of acknowledgments from receiver to sender. When data segments or acknowledgments are ...