## 1 Introduction  
The Smart Grid (SG) is the application of communication and information technology to the energy grids to manage the generation, delivery and consumption of the electricity. Figure 1 shows the system structure of the SG network. The Advanced Metering Infrastructure (AMI) is the new part of the Smart Grid which supports the transfer of two-way power and a high data rate by connecting Smart Meters (SMs) at user's homes to the Meter Data Management Systems (MDMS) in order to collect and manage data. The main structure used for the AMI network is made of one Data Collector (DC), which acts as a gateway between the gathered information from SMs at home's and the utilities companies. In this paper, we are focusing on the communication network between data collectors and smart meters using wireless sensors environment. In the PLC (IEEE P1901.2) standard [1] networks, it is impossible and very hard for most of the nodes to communicate directly due to many reasons: noises distance, etc. So, each node should collaborate by relaying different frames to have the ability to reach all nodes in the network. Many routing protocols are designed to select, maintain and construct the best paths to route packets from source to final destination. Routing process in (AMI) networks is considered as a critical issue when designing its communication network. A routing protocol survey is presented in [2] that focused only on two different communication infrastructure components of the SG, namely, Neighborhood Area Networks (NANS) and Home Area Networks (HANS). Routing protocols for HANS are categorized depending on the type of communication as some networks use Power Line Communications (PLC) technologies [3] and others use wireless communication. On the other side, routing protocols for NANS are categorized based only on the application requirements. AMI is the most challenging application of SG that utilizes NANs. The communication infrastructure design of an electric power network is considered as a hot research area which attracts both industry and academia. The large-scale communication network of SG consists of three basic parts: Access area, distribution infrastructure, and the core network. Homes, buildings and industrial collections organize the access area which is responsible for delivering, SG services to end costumers and providing user contribution to electricity production. Distribution infrastructure makes the collection of electricity usage data, and the core network is responsible for the management and control based on the received data from the aggregator center. AMI represents an example of the distribution infrastructure that connects smart meters at the user side with data aggregation center at the company side using PLC networks and wireless sensors networks (WSN) communication. The AMI network provides information about the quality of power and quantity of consumption at the end user side. Devices in AMI networks based WSN are embedded devices with low computational and storage capability using low data rate and lossy radio communications. These kinds of networks are called Low Power and Lossy Network (LLN). Figure 1: Smart Grid Communication Network. Recently, RPL protocol is considered as the most preferred IPv6 routing protocol for large-scale low power and lossy networks. The IETF proposed RPL in 2008 and in March 2012 standardization was accomplished [4]. The new release of RPL standard has been designed to support and provide the routing requirements of the AMI application based WSN. AMI is expected to support two-way communications which allow a third-party company (e.g., Electricity companies) to keep track of electricity usage, inform customers with latest prices of electricity and performs remote management within a real-time basis.