The Transmission Control Protocol (TCP) is the most widely used transportprotocol in the Internet today. The problem of poor TCP performance oversatellite networks has recently received much attention, and much work hasbeen done in characterizing the behavior of TCP and proposing methods forimprovement. Meanwhile it remains hard to upgrade the majority of legacyhost and gateway systems in the Internet that are running old and outdatedsoftware so that they can perform better in the changing networks of today.

In this thesis we consider an alternative network architecture, where largeheterogeneous networks are built from small homogeneous networksinterconnected by carefully designed proxy systems. We describe the designand implementation of such a proxy and demonstrate marked performanceimprovements over both actual and simulated satellite channels. We alsodiscuss some benefits and drawbacks of using proxies in networks andexplore some tradeoffs in proxy design.