The paper shows the main problems that the Transmission Control Protocol (TCP) meets in a Geo Stationary Orbit (GEO) satellite environment characterized by high `delay per bandwidth product'. In a GEO environment, the delay in the delivery of a message is very high, the Round Trip Time (RTT) is above 500 ms. These characteristics heavily affect the acknowledgement mechanism on which the TCP is based and the performance of the protocol is much lower than in cable networks.
The paper proposes and analyses possible solutions aimed at mitigating the negative effect and at improving the performance.
A real test-bed is used to carry out the study: two remote hosts are connected together through a satellite link in the Ka-band (20ยฑ30 GHz) by using IP routers. The system has been tested by using a ftp-like application, that allows transferring data of variable size between the two hosts. This is due to the observation that most of the Internet multimedia applications, as browsing and distance learning, use massive ยฎle transfer.
The protocol behavior is investigated both by tuning the parameters buffer size and initial congestion window and by modifying the dynamic characteristics of the slow start algorithm. The analysis itself allows suggesting solutions and taking decisions.