In 6LoWPAN, an adaptation layer is implemented between the network and the data link layers to fragment and reassemble the IPv6 packets which are much larger than the packet size of IEEE 802.15.4 data link layer.
Routing in 6LoWPAN can be divided into two ways, based on the layer on which the routing decision is taken.
In route-over, IP packet is fragmented and all fragments are sent to the next hop. The next hop checks all fragments for error and create IP packet. It is more reliable than the other way, however, Route-Over increase overheads to reassemble fragments at each hop.
The other is mesh-under that transmits all fragments from source to the final destination. In this scheme, for error recovery end-to-end retransmission is done.
This Thesis proposes the way to reduce time and energy when the fragmented packets need to be retransmitted by using powerful node, which is located at an appropriate place.
