The Internet of Things (IoT) is the collection of low-power devices deployed in real-time applications like industries, health care and agriculture. The real-time applications must quickly sense, analyze and react to the data within a time frame. So the data’s should be transmitted without any delay. The Routing Protocol for Low-power and Lossy Networks (RPL) is used to route the data by finding the optimal path. RPL forward the data packets from source to destination based on the objective functions. The objective functions can be designed using different routing metrics and most of the existing objective functions are not designed based on the characteristics of IoT applications. The Industrial Internet of Things (IIoT) environment with real- time data transfer characteristic is considered for this proposed work. Packet loss, power depletion and load balancing are the problems faced by real-time environment. Neighbor Indexed based RPL (NI-RPL) is implemented in two steps to improve efficiency of RPL. First, based on the Received Signal Strength Indicator (RSSI) and path-cost the preferred-parent set is formed from the set of neighboring nodes. Second, the rank of the nodes from the preferred-parent set is calculated based on the Neighbor Index (NI), Expected Transmission count (ETX) and Residual Energy (RE), and then the best route is selected based on the rank. The NI is used to avoid congestion, the ETX and RE helps in improving the Quality of Service (QoS) and lifetime of the network. The proposed objective function, NI-RPL is compared with other objective functions. NI-RPL guarantees the delivery of real –time data with better QoS, because it has improved the packet delivery ratio by 3% to 5% and decreases latency by 7 to 12 seconds.

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