The Design And Implementation Of An UDP-based P2P Instant Messaging Software

This comprehensive introduction to the completion of an independent development of the UDP-based P2P instant messaging software related theoretical background and detailed design and implementation. The software runs on Linux/Unix terminal environment, to fill the terminal environment open source instant messaging software blank. Design and implementation of software specifically related to the instant messaging software needs analysis, based on the UDP application-layer protocol design, P2P technology principle and method of information encryption and decryption algorithms, UDP concurrent server design paradigm to enhance the software User experience and network communications software debugging method and many other contents of testing.UDP-based application layer communication protocol design and implementation process of this software as a key issue. Characteristics of unreliable UDP protocol cannot directly allow us to communicate with it. The software communication protocol used the confirmation and retransmission mechanisms to ensure reliability of data transmission, using the dynamic retransmission timer timeout value increases the adaptability and flexibility of the agreement also used the data in the application layer approach to avoid fragmentation of the IP layer of the low efficiency of fragmentation. Another problem is the key issue between the client P2P (point to point) communications. P2P communication must be a problem to be solved is to penetrate NAT devices. The software uses a feature called "UDP hole punching" method to establish P2P connection, this method is simple, penetrating ability, consistent with both the software architecture. In addition, the software implementation process, dig in the terminal environment, the presentation of information to optimize the user process, in many details to enhance the user experience and improve the software's ease of use.This software is to fill the Linux/Unix terminal environment open source instant messaging software blank, providing a user-friendly instant messaging tool. The software is stable and the user experience is good, and there is low resource consumption, and communications have high efficiency. The author hopes that more volunteers to its continuous improvement and improved to be more widely used.