CAEsAR: A Context-Aware Addressing and Routing Scheme for RPL Networks

The Internet of Things is changing today from a daring vision to reality. Sensors, smartphones, smart vehicles are all around, transforming the physical world into an intelligent environment able to provide context-aware services. To support this, we must propose communication protocols that consider the special requirements of IoT. The 6LoWPAN and RPL protocols were defined for this purpose, enabling IoT devices with scarce resources to get an IPv6 address and connect to the Internet. However, the basic principles of communication have to be adapted also. Instead of using the address of a sensor, we query IoT devices based on their context. Also, we need information from the environment, no matter which IoT device provides it. This is the governing principle of data-centric communication, an area that gets increasing attention and fits perfectly the IoT. Here we propose CAEsAR, a Context-Aware Addressing and Routing scheme. It uses RPL trees and aggregates context information in Bloom-filters along the tree. We compare CAEsAR with an IoT service discovery protocol called TRENDY, and the data-centric protocol called MQTT-SN. Simulations show that CAEsAR generates much less signaling traffic, both in the RPL tree setup phase and when the system adapts to changes of context parameters.