TCP proxy over Delay Tolerant Networks (DTN)

Abstract

The emergence of challenged networks characterized by long end-to-end delay, non-continuous connectivity, high error rate and asymmetric data rate has motivated the research and standardization of DTN (Delay Tolerant Network) to improve the poor performance by TCP/IP protocol suite deployment in these networks. The objective of the project is to develop a proxy to enable TCP applications to run over DTN. The proxy design adapted the PEP’s (Performance Enhancing Proxy) approach of splitting network connection.

The project goal has been achieved as the TCP proxy developed can allow general TCP packets to be transmitted over DTN, in both normal condition of continuous connectivity and extreme condition of very long delay and disrupted connectivity. Other common TCP applications, namely HTTP and SSH have been successfully tested to function properly over DTN. The exception is FTP as its operation specification requires special handling by the proxy which cannot be supported by the general TCP proxy designed. This is thus a limitation of the developed TCP proxy.

The project outcome not only demonstrates the functionality and usability of DTN in wireless intermittent-connectivity networks but also successfully explores the possibility of using proxy to enable existing TCP applications to run in DTN environment.

For future work, the recommendations to improve the proxy performance and functionality include developing specialized proxy to handle FTP and designing the TCP proxy to be located within the realms of the router instead of the current implementation of having the TCP proxy being co-located within the same node as the TCP applications.