Hierarchical routing algorithm based on link quality for 6LoWPANINTRODUCTIONWireless sensor network (WSN) is today one of the areas to the fastest growing network in the world. In order to convert WSN from Personal Area Network (PAN) to Low Power Personal Area Network (LoWPAN), the IEEE 802.15.4 standard was introduced. However, future WSNs would consist of thousands of nodes and these networks could be connected to others via the Internet. Therefore, IPv6 over LoWPAN (6LoWPAN) is defined by the Internet Engineering Task Force (IETF) as a technique for integrating Internet capacity into the WSN. 6LoWPAN provides a WSN node with IP communication capabilities by placing an adaptation layer on top of the IEEE 802.15.4 link layer for the purpose of packet fragmentation and reassembly. The 6LoWPAN concept was born from the idea that "the Internet Protocol could and should be applied to even the smallest devices", and that low-power devices with limited processing capabilities should be able to participate in the Internet of Things . The arrival of 6LoWPAN enables the development of IP applications for low-power wireless networks such as sensor networks. There are often unreliable radio channels or frequent node failures in sensor networks and the question arises how applications based on 6LoWPAN can be hardened against such problems. 6LoWPAN consists of a huge address pool sufficient for future Internet-enabled devices. The Internet Engineering Task Force (IETF) standardized the transmission of IPv6 over LoWPANs through 6LoWPAN and an adaptation layer was introduced with various mechanisms such as header compression, packet fragmentation and reassembly at the -on top of the logical link layer of the IEEE 802.15.4 protocol stack. The baseline model of 6LoWPAN protocol indicates that the proposed algorithm requires very less time and hence becomes more efficient. Figure 2 Routing Overhead The above simulation result shows the routing overhead with the blue line representing series 1 for the basic HiLOW protocol and the red line for series 2 for the proposed HiLOW based on link quality . The above result clearly shows very low routing overhead in the case of the proposed algorithm and proves that the proposed algorithm would provide a better routing structure. Figure 3 Packet Drop Rate The above graphical result depicts how the proposed HiLOW protocol has a lower packet drop rate as shown by the series of blue lines compared to the series of red lines representing the baseline HiLOW . The low packet drop rate shows that when routing is carried out with the best link quality, more packets reach the destination and the routing efficiency is greatly improved..