# Multiple Instances QoS Routing in RPL: Application to Smart Grids +
## 2 Related Work
### Why Multiple Instances? SG applications are heterogeneous in terms of requirements, criticality and delay tolerance [3; 4; 5; 34]. Guaranteeing that each of these applications meets its QoS demands requires a multi-objective solution. As an example, we can cite some of the following main SG applications and their requirements. * Advanced Metering infrastructure (AMI) consists of an integrated system of smart meters for measuring, collecting, analyzing and communicating energy consumption of smart appliances. Enabling two-way communication between utilities and customers and providing a number of important functions that were not previously possible or had to be performed manually, such as the ability to automatically and remotely measure electricity use, connect and disconnect to a service, identify and isolate outages, and monitor voltage. * Demand Side Management (DSM) consists of a set of interconnected and flexible programs which grants customers a greater role in shifting their own demand for electricity during peak periods, and reducing their overall energy consumption. DSM comprises two principal activities:
* Demand Response (DR) or load shifting which aims to transfer customer load during periods of high demand to off-peak periods. The grid operator or other stakeholders influence the customers behavior mostly by monetary incentives, allowing them to participate in the energy market competition by changing their energy consumption approach instead of being passively exposed to fixed prices, which results in profits for both, the companies and the end-users. * Energy efficiency and conservation programs which allow customers to save energy while receiving the same level of end service, such as when they replace an old electric appliance with a more energy efficient model. * Distribution Automation (DA) is defined as the ability of taking an automated decision to make fault detection, more efficient isolation and restoration in a grid by remotely monitoring, controlling, manipulating and coordinating distribution, improving then the reliability accross the grid. DA offers new functionalities, incorporate alarming and automated feeder switching, which in turn will help reduce the frequency and duration of customer outages. Substation automation is achieved through Supervisory Control and Data Acquisition (SCADA) systems which are able to make these automated decisions in real time by running algorithms based on the data they receive and orchestrate adjustments to optimize voltages and self-heal any failure issues. * Distributed Energy Resources (DERs) such as photo voltaic cells, wind turbines and energy storage points present one of the main benefits in a SG. These DERs will be able to supply particular areas with electricity when they are isolated from the main power grid due to failure conditions or system and equipment failures. Moreover, these DERs foster the shift from a centralized power system towards a more decentralized system by contributing to the evolution of local grid areas served by one or more distribution substations and supported by high penetrations of DERs called microgrids. * Electric transport via electric vehicles (PEV: Plug-in Electric Vehicles) or hybrid electric vehicles (PHEV: Plug-in Hybrid Electric Vehicles) aims to improve or even replace traditional transport by reducing emissions produced by fossil fuels. For that, an electric vehicle uses one or more electric motors that are powered by a rechargeable electric accumulator. SGs can better manage vehicle charging so that rather than increasing peak loads, the charging can be carried out more strategically, when for example electricity demand is low or when the production of renewable electricity is high. In the long run, SGs can use electric vehicles as batteries to store renewable and other sources of electricity for later use. However, since these applications will generate different types of traffic (real-time, critical, regular) [6], they require different levels of QoS.