The previous article covered a basic introduction to IP enabled Smart Objects. These are devices that combine processing power with communications capabilities to exchange information using the Internet Protocol. IP Smart Objects are being deployed in a variety of machine to machine (M2M) systems. Application areas such as industrial control, process automation, and commercial building control are moving away from closed proprietary protocols to embrace open international standards such as the Internet Protocol (IP). Now the U.S. Smart Grid has adopted IP to interconnect smart energy components such as smart meters and thermostats, which will amount to 300–500 million devices.
Previously, it was thought that IP couldn't be made to work for the Smart Grid since the Smart Grid requires low output power, low cost, low duty cycle, and small memory and code footprints. However, IPSO Alliance Interops (interoperability demonstrations) have proven that IP can be implemented on microcontrollers and radios that cost less than $2.00. An IPv6 Ready compliant stack can be built in <12 K bytes of code and requires < 2K bytes of RAM. In a network built for Consumers Energy of Michigan, Proto6 demonstrated Web traffic (HTTP over TCP over IPv6 with 6lowpan) traversing multiple low-power Atmel IEEE 802.15.4-compliant radios using an IP stack similar to the one just described. The data was sent over 10 hops to a completely standard Apache Web server.
The Smart Grid isn't a single network or simply the electric meter on the side of a house or building. It is a network of networks and devices that includes these meters as well as other devices outside the home such as substations, re-closers, transformers and generators (Figure 1). Examples of Smart Objects inside the home include thermostats, in-home displays, electric water heaters, plug-in hybrid electric vehicles (PHEV), and energy management systems. These devices will be connected to different networks such as the HAN (Home Area Network) or the SUN (Smart Utility Network—previously known as the Neighborhood Area Network or NAN) or on other private utility networks.
Moving to an all IP network (also called IP to the Edge) provides a number of benefits over proprietary networks. Because every organization already has and supports IP-based systems and networks, extending the Smart Grid using IP will allow companies and utilities to leverage existing network management tools and knowledge, eliminating the need for retraining on multiple proprietary networking tools or new protocols. Additionally, by using IP, interconnecting and interoperating with the systems and networks already installed becomes trivial and the Smart Grid becomes an extension of these networks.
The use of IP in the Smart Grid offers a well-understood and widely-used naming and addressing system. IPv6 will provide a nearly limitless supply of addresses so that every object or device in the Smart Grid network can be given an address. Unlike IPv4, where infrastructure devices such as NAT (Network Address Translation) and DHCP (Dynamic Host Configuration Protocol) servers are required, IPv6 uses a built-in technology called StateLess Address AutoConfiguration (SLAAC). This allows each device to automatically "learn" its IP address. In addition, the Domain Name System (DNS) that is used today on the Internet is ready and able to work with IPv6 addresses.
A disadvantage of proprietary solutions is that they are tied to a particular network technology such as power line communications (PLC), Ethernet, narrow-band frequency hopping, or cellular. IP runs on top of most communications media. Smart Grid products and solutions can choose the technology most appropriate to solve the problem at hand. For a low-power, low-cost wireless network, IEEE 802.15.4 can be used. If greater distances are needed then IEEE 802.11 (WiFi) can be selected. For even greater coverage IEEE 802.16 (WiMax) or cellular could be installed. If wired communications is required then RS-485, PLC, cable, DSL, or Ethernet might be chosen.
Since IP can run seamlessly across all of these types of networks, there is no need for gateways that translate from one protocol to another. This both simplifies the network design and improves security. An IP solution can use existing cable modems or DSL routers, thus reducing management cost and overhead. Gateways and protocol translation have an inherent problem—they "break" the security of the protocol. They divide the security domain into two separate pieces—one inside the gateway and one outside. To translate from one protocol to the other, the gateway must decrypt and then re-encrypt the message. Because there is a period of time when the message is "in the clear", this introduces an attack point where messages can be intercepted or inserted. An end-to-end IP network can encrypt the message at the source and only decrypt it once it reaches its destination, ensuring the integrity and security of the message.
Many have tried to justify the use of proprietary solutions by claiming that IP is not secure. The IPSO Alliance has published a white paper, "Introduction to Security for Smart Object Networks" that discusses the benefits of the IP security model and the steps necessary to ensure a secure solution. The fact is that some of the most secure and sensitive networks in the United States use IP. The protocol is well understood, tools such as firewalls and packet filters are commercially available, and the security architecture has been well-vetted over the past 40 years of use.
By basing the U.S. Smart Grid on an end-to-end IP infrastructure we can simplify the overall design. NIST has set up a Priority Action Plan team (PAP1) to define an IP-based Smart Grid Architecture so that we can take advantage of years of experience and make use of currently deployed services and protocols. By moving away from proprietary protocols and toward using IP, all of the networks and devices that will make up the Smart Grid can be cohesively and seamlessly interconnected. In the end this will reduce costs of installing and managing the network, the devices and the Grid and will translate into savings to the rate payer—you and I.
More information about how IP will be used, including the Utility Industry's perspective from Duke Energy will be provided at the upcoming IPSO Webinar on September 14, 2010. Visit the IPSO Web site for details.
Geoff Mulligan, a longtime network technologist, is chairman of IPSO Alliance, which advocates for use of Internet Protocol as the standard for smart object communications. He can be reached at [email protected].