Research Of Routing Optimization And Trust On LR-WPAN

When thinking about sensor networks the first thing that does not come to mind is the use of the Internet Protocol (IP). IP has always been considered the protocol for Local Area Networks or Wide Area Networks, PCs and Servers. It was not thought appropriate for sensor networks, Personal Area Networks and the sensors themselves because of the perception that it was too heavy weight for these applications.Utilizing IP in these networks and pushing it to the very edge of the network devices flattens the naming and addressing hierarchy and thereby simplifies the connectivity model. This obviates the need for complex gateways that, in the past, were necessary to translate between proprietary protocols and standard Internet Protocols and instead can be replaced with much simpler bridges and routers, both of which are well understood, well developed and widely available technologies. Additionally by using IP based protocols users can employ tools already developed for commissioning, configuring, managing and debugging these networks. It is not necessary to develop an entire new set of tools to deal with proprietary protocols and applications and to develop the skills necessary to use those tools. Since the entire network is IP based, programmers and administrators do not need to learn and develop expertise in a new programming paradigm. The network is programmed and functions the same as other Internet applications. When it is necessary to debug the network or application, engineers will already have the experience of debugging IP based network glitches.6LoWPAN protocol can enable IPv6 packets to be carried on the IEEE 802.15.4 based networks. It is suitable for the handset devices because of the lower power consumption, and the build-in AES-128 modes make it easy to authentication.There is an adaptation layer between network layer and link layer in 6LoWPAN, which makes it possible to transmit IPv6 packets over 802.15.4. The adaptation layer provides a header compression to reduce transmission overhead, fragmentation to support the IPv6 minimum MTU requirement, and support for layer-two forwarding to deliver an IPv6 datagram over multiple radio hops.6LoWPAN achieves low overhead by apply cross-layer optimizations; it uses information in the link and adaptation layers to compress network-and transport-layer headers. Drawing on IPv6 extension headers, it employs the "header stacking" principle to separate the orthogonal concepts and keep the header small and easy to parse.Depending on which layer packets forwarding occurs within the LoWPAN, there are two types of routing in 6LoWPAN network:Mesh Under and Route Over. In a Mesh Under organization, packets forwarding occurs in link layer or adaptation layer by using link layer address, and in Route Over organization, packets are forwarded link most of the IP-based routing protocols, every device performs as a router.There is more research on layer-three forwarding within 6LoWPAN, which can make use of the protocols in IP-based network. But we can reduce processing time of the packets and simplify data processing when using Mesh Under organization, and only link layer address need to be resolved.In this paper, we analyze a hierarchical routing protocol in 6LoWPAN and improve it in two ways:first, we change the strategy of choosing a parent node when the device joins the network;second, we propose a routing recovery strategy when node failure appears. Simulation result shows that this hierarchical protocol has a better performance and the routing recovery works.