The main objective of Internet of Things (IoT) is to connect almost all the devices anywhere and everywhere in the world. IoT network is heterogeneous in nature, hence routing the data packets in this network is a big challenge. Routing Protocol for Low Power Lossy Network (RPL), has been designed by Internet Engineering Task Force (IETF) for such type of network. The existing design of RPL Objective Function (OF) is insufficient to cover all the issues of IoT applications. In this paper, the proposed OFs designs using various routing metrics are used to enhance the performance of the IoT applications. The analysis for various scenarios for these designs shows that only traditional hop and Expected Transmission Count (ETX) routing parameters will not fit for the smart applications need. The routing metric selection according to the application requirement is the principal idea of the proposed design. Three metrics ETX, Content and Energy, single and combination with each other are used to enhance the design of objective function of RPL for IoT applications. The enhanced triggering technique is added in these designs for the improvement of RPL. This technique will eliminate the cumulative effect of the short-listen problem of default trickle timer. The result analysis done using Cooja simulator along with Contiki Operating System (OS) states that, all the designs are performing well in one or other manner than the traditional OF. Energy combined with Content (EC) and aggregation with Enhanced timer (EC_En_Timer) design gives better result for Packet Delivery Ratio (PDR) and Latency Delay (LD) as compared to default OF design. Residual Energy (RE) combined with ETX (EE) and conjunction with Enhanced timer (EE_En_Timer) design works well for energy consumption. Overhead is very less in RE and ETX design. Conversion time is reduced by almost 50% in an En_Timer design. Higher PDR and low delay values of EC and EC_En_Timer design encourages its use in health monitoring application where reliability is essential. Low energy consumption results of RE, EE and EE_En_Timer designs are comfortable for forest monitoring application, as energy is a crucial aspect. This comparative result outcome will help to fulfill the IoT application requirements.

物联网（IoT）的主要目标是连接世界各地几乎所有设备。物联网网络本质上是异构的，因此在此网络中路由数据包是一个巨大的挑战。Internet工程任务组（IETF）已针对此类网络设计了低功耗有损耗网络（RPL）的路由协议。RPL目标功能（OF）的现有设计不足以涵盖IoT应用程序的所有问题。在本文中，使用各种路由度量的拟议OF设计可用于增强IoT应用程序的性能。针对这些设计的各种方案的分析表明，仅传统的跃点和预期传输计数（ETX）路由参数将无法满足智能应用程序的需求。根据应用需求选择路由度量是本设计的主要思想。使用三个指标ETX，内容和能源，单个和彼此结合来增强IoT应用程序RPL的目标功能设计。在这些设计中添加了增强的触发技术以改善RPL。此技术将消除默认trick流计时器的短听问题的累积影响。使用Cooja模拟器和Contiki操作系统（OS）进行的结果分析表明，与传统OF相比，所有设计都以一种或其他方式表现良好。与默认OF设计相比，将能量与内容（EC）结合并使用增强型计时器（EC_En_Timer）设计进行聚合可为数据包传输率（PDR）和延迟延迟（LD）提供更好的结果。剩余能量（RE）与ETX（EE）结合使用，并与增强型计时器（EE_En_Timer）结合使用，可以很好地降低能耗。RE和ETX设计的开销很少。在En_Timer设计中，转换时间减少了近50％。EC和EC_En_Timer设计具有较高的PDR和较低的延迟值，因此鼓励将其用于对可靠性至关重要的健康监控应用中。RE，EE和EE_En_Timer设计的低能耗结果非常适合森林监测应用，因为能源是至关重要的方面。这一比较结果将有助于满足物联网应用需求。在En_Timer设计中，转换时间减少了近50％。EC和EC_En_Timer设计具有较高的PDR和较低的延迟值，因此鼓励将其用于对可靠性至关重要的健康监控应用中。RE，EE和EE_En_Timer设计的低能耗结果非常适合森林监测应用，因为能源是至关重要的方面。这一比较结果将有助于满足物联网应用需求。在En_Timer设计中，转换时间减少了近50％。EC和EC_En_Timer设计具有较高的PDR和较低的延迟值，因此鼓励将其用于对可靠性至关重要的健康监控应用中。RE，EE和EE_En_Timer设计的低能耗结果非常适合森林监测应用，因为能源是至关重要的方面。这一比较结果将有助于满足物联网应用需求。