European Space Agency

TRANSAT - Transport Protocol and Communication Resource Management for Mobile Satellite Networks


The Internet TCP protocol, part of the TCP/IP suite, is one of the cornerstones of the Internet. However, TCP was not designed for optimising resource usage, and has inherent performance problems over many types of satellite links, in particular mobile links. In order to make efficient use of expensive satellite transponder resources, many satellite communication networks use various types of Dynamic Assignment Multiple Access (DAMA) protocols for allocating resources according to the instantaneous needs of the various data streams in the system. Such protocols are typically found in mobile satellite communication as well as in many VSAT systems. The purpose of the work is twofold:

1.       To develop a new transport protocol for the satellite link, which makes it efficient to use satellites in internet-based networks or multimedia applications while maintaining compatibility with existing applications and networks.

2.       To investigate methods for explicitly communicating resource requirements and availability between the application and the DAMA control. The preferred solution is one that operates completely within a standard protocol stack, with the exception that the application and the DAMA control need to be aware of each other, and expl


Not Applicable.


This proposal addresses long-standing problems in satellite communication. It aims at devising a generally applicable solution to the problems, as well as demonstrating this solution within a real satellite communication system. Although several activities are under way in the Internet Engineering Task Force (IETF) to attempt to improve TCP performance over satellite links, no known initiative is looking into replacing TCP with a more suitable protocol (while maintaining application compatibility). In many ESA satellite communications projects, emphasis is put on efficient use of resources, and it is felt that the proposed activity fits well into this picture, and that ESA could have a role world wide in furthering this particular field. Apart from being applicable to mobile satellite and VSAT systems it should also be relevant to terrestrial (cellular) mobile links and wireless LANs.


Not Applicable.


Three parallel contracts to three different consortia have been awarded to carry out this activity. For each parallel contract the activity has been divided into two different phases.

Current status

Work completed.

Final presentation took place 26 May 2004.

The executive summary and the final presentation slides are available. Some follow-on work under a CCN to the contract is currently being contemplated.

Status date

Thursday, February 7, 2008 - 15:05