Research On Packet Forwarding Policy Managed For Railway Wireless Mesh Network

Based on the banyan-tree topology railway wireless Mesh network having the advantages of bus and star topology which makes broadband Internet to be along the railway line provides a more reasonable solution. However, unlike traditional wireless campus and enterprise networks, railway wireless Mesh network usually has the coverage of geographical span as long as hundreds of thousands of kilometers. How to make this new network form to ensure effective management for highly efficient data communications has become one of the key issues on the application of the Internet to the train.In support of users'fast-moving, railway wireless Mesh network generally realizes data communications by MAC packet forwarding program. Therefore, this paper firstly deeply analyses the basic functions of the MAC Bridge according to IEEE 802.1d-2004 protocol and based on the Linux open source codes focuses on an analysis of realization and processing of MAC packets forwarding in the Linux kernel. In the following, by a detailed analysis of the railway wireless Mesh network structure and application requirements the author finds out the shortcomings and deficiencies of the traditional packet forwarding strategies and the network management protocol; this paper proposes and designs a MAC packet forwarding policy for rail wireless Mesh network, then design and detailed analysis on the key points such as selective packet forwarding, neighbor nodes status report mechanisms, intelligent network management and so on are carried out. Finally, the author does a lot of specific codes changes and program design on bridge modules of the Linux 2.6.19 kernel source code, and then a specific program implementation of the data packet forwarding policy are put forward. In the embedded Linux platform, the test bed for the railway wireless Mesh network is built, and then experiment research and functions verification for before and after the improvement of packet forwarding policy have been tested. Theoretical analysis and experimental results show that the design of packet forwarding policy put forward in the article can achieve a good management / user selectively forwarding packets, also after detecting or predicting node failure, the switch center can make the timely adjustment to the data packet forwarding path. At the same time, this improved network increases very small overhead and can very well to achieve a long-distance intelligent network management for railway wireless Mesh network which can enable railway wireless Mesh network to ensure efficient data communication.