TCP - Impact of link characteristics

The TCP protocol was conceived in the early 1980s in a context of network technologies that were very different from those of today. Although its longevity is a testament to its robustness, technological developments – such as increased data rates and the heterogeneous nature of today's networks (wireless links, cellular networks, asymmetrical access networks, etc.) – pose serious performance problems for TCP. TCP is capable of adapting to a wide variety of network conditions (in terms of available bandwidth, delays, losses, etc.), but this comes at the price of significant consequences for the protocol's behavior.

As the study and improvement of TCP as a whole is too vast a subject, the aim of this dossier is to present some performance problems due to link characteristics and low-layer technologies. An overview is also given of possible evolutions and modifications to TCP, aimed at alleviating these problems. Many of the techniques illustrated here are still in the field of research, and the emphasis is mainly on those that have been the subject of an Experimental RFC at the IETF.

This file complements two others: "TCP transport protocol". and "TCP: protocol performance and evolution". by the same author.