1. Introduction

Satellite channel characteristics may have an effect on the way transport protocols, such as the Transmission Control Protocol (TCP) [Pos81], behave. When protocols, such as TCP, perform poorly, channel utilization is low. While the performance of a transport protocol is important, it is not the only consideration when constructing a network containing satellite links. For example, data link protocol, application protocol, router buffer size, queueing discipline and proxy location are some of the considerations that must be taken into account. However, this document focuses on improving TCP in the satellite environment and non-TCP considerations are left for another document. Finally, there have been many satellite mitigations proposed and studied by the research community. While these mitigations may prove useful and safe for shared networks in the future, this document only considers TCP mechanisms which are currently well understood and on the IETF standards track (or are compliant with IETF standards).

This document is divided up as follows: Section 2 provides a brief outline of the characteristics of satellite networks. Section 3 outlines two non-TCP mechanisms that enable TCP to more effectively utilize the available bandwidth. Section 4 outlines the TCP mechanisms defined by the IETF that may benefit satellite networks. Finally, Section 5 provides a summary of what modern TCP implementations should include to be considered "satellite friendly".