Research And Implementation Of Gateway Key Technology Interconnecting 6LoWPAN To IPv4 Network

The integration of WSN and Internet has become a research focus, and demands for IP based wireless sensor networks are becoming increasingly urgent. In view of this, the standards of IPv6 over Low Power Wireless Personal Network(6LoWPAN) were proposed, there is no doubt that 6LoWPAN technology contributes to achieving WSN access to Internet, but now Internet is mainly based on IPv4(Internet Protocol Version 4), the transition from IPv4 to IPv6 is a long process, 6LoWPAN can not directly communicate with IPv4 networks. Accordingly, the problem of IPv6 communicating with IPv4 must be solved to achieve the interoperability between 6LoWPAN and IPv4 networks.One of the research targets of The National Major Project of Science and Technology “Development and Verification of the Network Protocol of WSN Based on IPv6” is to complete the research of key technologies used to achieve the interconnection between 6LoWPAN and IPv4 networks, and then the technology must be implemented in the gateway which is also developed in this project. Therefore, this thesis, based on the above project, will focus on the issue of integrating 6LoWPAN and IPv4 networks. The main research work includes:1. To summarize the current development of WSN and Internet, analyze and compare a variety of techniques about WSN accessing to Internet, finally select a protocol translation technology which is implemented in the following chapters to achieve the interconnection of 6LoWPAN and IPv4 networks.2. For solving the problem that 6LoWPAN cannot directly communicate with IPv4 networks because of the distinction of their network layer protocol, firstly, the 6LoWPAN stack is transplanted from cc2530 to ARM9 platform to make the 6LoWPAN network access to IPv6-supported gateway, and then the uNAT64(Micro Network Address and Protocol Translation) is implemented in the gateway to translate 6LoWPAN packets to IPv4 packets and vice versa, furthermore the interconnection between 6LoWPAN and IPv4 networks can be achieved based on the above mentioned implementation.3. For solving the problem of multiple dataflow chaos and collision in the IPv6-supported gateway, a solution of multiple dataflow path planning is proposed, which classifies packets according to processing mode by which the gateway handles them, design a packet filtering algorithm to ensure that the multiple dataflows can be transported in planned path.4. To set up an experimental platform to test the functions and performances of IPv6-supported gateway, the functions include uNAT64 protocol translation, WSN accessing to gateway and gatway accessing to IPv4 networks, the performance indexes include the throuthput, packet loss rate, processing delay, network scale and stability. The test results demonstrate that the uNAT64 mechanism based on IPv6-supported gateway platform can interconnect 6LoWPAN to IPv4 networks, the gateway and 6LoWPAN can run stably for a long time, meanwhile the gateway can also support the WSN monitoring service for the system managers.