中文摘要：

在基于Mesh-under路由的6LoWPAN网络中，链路丢失的分片采用端到端的方式进行重传，从而保证数据包的可靠重组，但端到端的重传会造成较多的数据传输时延和网络能耗，降低目的端的分片重组成功率，影响网络中其他数据的有效传输。针对上述问题，提出一种基于中间节点缓存与重传分片机制，通过中间节点缓存和管理所转发分片，目的端检测到有分片丢失，则利用中间节点已缓存的分片进行重传，从而达到提高网络性能的目的。仿真结果表明，与传统的RIF—SN，RPF—SN等机制相比，该机制能耗效用值提高36．7％，网络传输时延减少28．7％，目的端重组成功率提高34．9％，明显改善网络性能。

英文摘要：

In IPv6 over Low-power Wireless Personal Area Networks（6LoWPAN） based on Mesh-under routing, the missing fragmentations are retransmitted with the end-to-end method to ensure the reliable reassembly of packets. But the end-to-end retransmission can result in the large data transmission delay and energy consumption, decrease the destination＇ s reassembly successful rate and influence other data＇ s transmission. In order to solve the problem, a cache and retransmission mechanism based on the forwarding intermediate nodes is proposed. The intermediate nodes can cache and manage the forwarding fragmentations, and the destination node＇ s missing fragmentations are retransmitted by the intermediate nodes to improve the performance of the entire network. Simulation result shows that the performance of the proposed mechanism is better than the traditional RIF_SN, RPF_SN mechanism, the energy utility value can be drastically increased by 36.7% ,the delay is decreased by 28.7% and the packet＇ s reassembly rate increased by 34.9% .