Development of POP3 proxy for delay tolerant networks

• Main Author: Yulis.
• Other Authors: Yeo Chai Kiat
• Format: Final Year Project
• Language: English
• Published: 2013
• Subjects: DRNTU::Engineering::Computer science and engineering::Computer systems organization::Computer-communication networks
• Online Access: http://hdl.handle.net/10356/52090
• Institution: Nanyang Technological University

The Internet is one of the most popular media for information exchange among users nowadays. Nevertheless, there is intermittent connectivity causing data loss, long delays, and high bit error rate in the Internet. Packets might not be forwarded successfully and they will be dropped eventually due to intolerance to long delays and intermittent connectivity. Therefore, the DTN (Delay-Tolerant Network) was introduced as the DTN is able to tolerate long delays and intermittent connectivity in the networks. As email communication is widely used today, this project aims to design and develop a POP3 (Post Office Protocol version 3) proxy to operate in DTN. The developed POP3 proxy consists of two major components, namely, the POP3 proxy client and the proxy server, which are transparent to users and enable POP3 email applications to operate normally without knowing the existence of DTN and the POP3 proxy. The POP3 email applications will interact with their POP3 servers through the POP3 proxy sitting between the POP3 email applications and the Internet. Hence, if a network suffers long delays or intermittent connectivity, the POP3 email applications will still be able to retrieve their emails through the POP3 proxy over the DTN. The POP3 proxy has been successfully tested to operate correctly and satisfy its system requirements. It is able to handle multiple POP3 client connections simultaneously and tolerate long delays and intermittent connectivity. In a non-disrupted network, the email clients would be able to retrieve their emails correctly. However, in a disrupted network, some of the emails with attachments could not be retrieved correctly due to out-of-order packets received by the DTN agent. It is suggested that this limitation may be resolved by improving the DTN agent’s way in sending and receiving packets in an orderly manner using tag ID. For future development, the recommendations to improve the performance and functionality of the POP3 proxy include improving the POP3 proxy to more effectively prevent out-of-order email packets during network disruption and enabling the POP3 proxy to support secure POP3 communication.