Milestone in Connecting the Internet of Things – RPL Routing Standard Completed

After four years of hard work behind the scenes, Cisco is delighted today to say that new ground has been broken for IPV6 implementation. Ahead of World IPV6 Launch on June 6, the standardization of RPL, a new IPV6 routing protocol designed for large-scale implementation of IPV6 in harsh environments, has been completed.



What’s the significance of the standard, you might ask? The Internet of Things – the term used to describe the billions of intelligent end points that collect and send data back to a centralized computing resource like a server, or to each other. The Internet of things refers to IP private networks and smart objects connected to the public Internet. The number of applications is only bounded by imagination with applications on Smart Grid, Smart Cities, Industrial Automation, Connected Cars to mention a few. The number of things connected to the Internet exceeded the world population in 2008 – and will only grow. Projections have the number of things connected to the Internet at 50 billion by 2020.


Routing is a fundamental piece of the overall IPV6 architecture for the Internet of Things, and RPL will translate the potential of Internet of Things into reality. When many people think of devices connected to the Internet, they think of smartphones, tablets, laptops and desktops. They don’t often think of the devices that will greatly dwarf those personal computing endpoints in volume – gas pumps, for example, or cars, railroad tracks, weather sensors and smart meters to name a few. These devices live in the outdoors, sometimes in harsh weather conditions, 24 hours a day. And not only do they require physical design that will protect them from these elements, but also a robust networking protocol that will work in these harsh conditions as well, while providing high scalability.



It became clear as intelligent devices were proliferating into all aspects of life, that a new routing protocol would be required for devices on the smart grid as well as other smart devices operating in harsh environments such as smart grids, manufacturing plants, commercial buildings, and on transportation networks. The networks in these environments can be described as Low Power and Lossy Networks (LNNs), meaning they often operate with significant constraints on processing power, memory and energy—translating into high data loss rates, low data transfer rates and instability. Compounding these issues, LLNs are comprised of anywhere from a few dozen and up to thousands and even hundreds of thousands of routers handling point-to-point (device to device), point-to-multipoint (central computer to devices) and multipoint-to-point (devices to central computing) traffic. All of this adds up to what we engineers love: solving a good challenge!



So four years ago, in 2008, the Internet Engineering Task Force (IETF) formed a working group to specify the routing solution for LLNs. The protocol would address the issues outlined above, and would involve a successful collaboration between a number of stakeholders and other active IETF working group members.


Fast forward to today, and the protocol, called RPL, has been completed. The complete set of RPL routing standards are:



• RFC 6550: RPL: IPv6 Routing Protocol for Low-Power and Lossy Networks
• RFC 6551: Routing Metrics Used for Path Calculation in Low-Power and Lossy Networks
• RFC 6552: Objective Function Zero for the Routing Protocol for Low-Power and Lossy Networks (RPL)
• RFC 6553: The Routing Protocol for Low-Power and Lossy Networks (RPL) Option for Carrying RPL Information in Data-Plane Datagrams
• RFC 6554: An IPv6 Routing Header for Source Routes with the Routing Protocol for Low-Power and Lossy Networks (RPL)


To date, there have been a number of independent implementations and several deployments in the field using RPL, and other standards alliances have adopted RPL as the routing protocol of choice, including Zigbee/IP and Wave2M alliances.


For Cisco, RPL is a fundamental block in the end-to-end IPV6 Field Area Network architecture and will be used as the standard for other areas of the smart grid as well. We have several large-scale on-going deployments with million of nodes, and we successfully validated RPL. The results of the internal tests showed that RPL was performing extremely well, as expected, and also successfully passed a number of stress tests.



So where do we go from here? Cisco anticipates we will soon be able to report successful deployments in several utility networks. While the majority of the work is behind us with regards to developing, defining, validating and testing the RPL protocol, field deployments almost always present new challenges – and new learnings – that will help Cisco and others continue to improve the protocol as it is being used. For today, we’ll be celebrating this major milestone. Tomorrow, we’ll be working on RPL in the field to ensure it performs its part in making the vision of smart grid a reality. We will keep you posted on our stories, and look forward to hearing from you as well on your successful uses of RPL in the field.