Improving TCP over satellite¶

Tasks list¶

Introduction¶

When deploying terrestrial networks and particularly the internet, the need to ensure integrity in data transfer combined with the wish to divide fairly a bandwidth between users lead to the born of TCP, a well known transport protocol. It was developped for terrestrial networks where the delay between routers is few milliseconds and the transmission quality is quite constant. But when we want to use it for geostationary satellite links the inevitable delay of 250ms for a single hop become a problem to have good throughput.

Considering the huge number of terminals using TCP, an overhaul of the protocol is not conceivable. However we can have clever solutions to skirt the problem and improve the performances. In this project the solution we use is to break the TCP chain in isolating the satellite link with PEP (Performance Enhancing Proxy), which makes virtually transparent the use of a satellite link at the TCP level.

This report will first address the state of the art of TCP over a satellite link, then the network architecture and the equipment configuration will be issued. Finally, simulations and results about PEPsal will be assessed.

I - State of the art¶

1. Specifications of a satellite link¶

2. TCP improvements over a satellite link¶

3. PEP TCP¶

4. PEPsal¶

II - Network architecture and equipment configuration¶

1. Network architecture¶

2. Modem MDM 6000¶

3. PC Engines and PEPsal¶

III - Simulation and results¶

1. Simulation limitations¶

2. Simulation program¶

3. Simulation without satellite link¶

4. Simulation with faked satellite link¶

References¶

List of figures¶