As a growing number of observers realize, one of the most important aspects of the emerging Internet of Things is its incredible breadth and scope. Within a few years, devices on the IoT will vastly outnumber human beings on the planet—and the number of devices will continue to grow. Billions of devices worldwide will form a network unprecedented in history. Devices as varied as soil moisture sensors, street lights, diesel generators, video surveillance systems—even the legendary Internet-enabled toasters—will all be connectedin one fashion or another.
Some pundits have focused only on the myriad addresses necessary for the sheer arithmetic count of devices and have pronounced IPv6 sufficient for the IoT. But this mistakes address space for addressability. No central address repository or existing address translation scheme can possibly deal with the frontier aspects of the IoT. Nor can addresses alone create the costly needed networking “horsepower” within the appliances, sensors, and actuators.
Devices from millions of manufacturers based in hundreds of countries will appear on the IoT (and disappear) completely unpredictably. This creates one of the greatest challenges of the IoT: management. This is a matter both of scope and device capabilities.
These devices incorporate the processors, memory, and human interfaces necessary for traditional networking protocol stacks (typically IPv6 today), the human interfaces necessary for control, and an infrastructure for management (unique addresses, management servers, and so on).
Data exchanged by Internet of Things Devices
The kinds of information these hundreds of billions of IoT devices exchange will also be very different from the traditional Internet Much of today’s Internet traffic is primarily human-to-machine oriented. Applications such as e-mail, web browsing, and video streaming consist of relatively large chunks of data generated by machines and consumed by humans.
But the typical IoT data flow will be nearly diametrically opposed to this model. Machine-to-machine communications require minimal packaging and presentation overhead. For example, a moisture sensor in a farmer’s field may have only a single value to send of volumetric water content. It can be communicated in a few characters of data, perhaps with the addition of a location/identification tag. This value might change slowly throughout the day, but the frequency of meaningful updates will be low. Similar terse communication forms can be imagined for millions of other types of IoT sensors and devices. Many of these IoT devices may be simplex or nearly simplex in data flows, simply broadcasting a state or reading over and over while switched on without even the capacity to “listen” for a reply.
This raises another aspect of the typical IoT message: it’s individually unimportant. For simple sensors and state machines, the variations in conditions over time may be small. Thus, any individual transmission from the majority of IoT devices is likely completely uncritical. These messages are being collected and interpreted elsewhere in the network, and a gap in data will simply be ignored or extrapolated
Even more complex devices, such as a remotely monitored diesel generator, should generate little more traffic, again in terse formats unintelligible to humans, but gathered and interpreted by other devices in the IoT. Overall, the meaningful amount of data generated from each IoT device is vanishingly small—nearly exactly the opposite of the trends seen in the traditional Internet. For example, a temperature sensor might generate only a few hundred bytes of useful data per day, about the same as a couple of smartphone text messages. Because of this, very low bandwidth connections might be utilized for savings in cost, battery life, and other factors.
Loss of Data
Today’s traditional Internet is extremely reliable, even if labeled “best effort.” Overprovisioning of bandwidth (for normal situations) and backbone routing diversity have created an expectation of high service levels among Internet users. “Cloud” architectures and the structure of modern business organizations are built on this expectation of
Internet quality and reliability.
But at the extreme edges of the network that will make up the vast statistical majority of the IoT, connections may often be intermittent and inconsistent in quality. Devices may be switched off at times or powered by solar cells with limited battery back-up. Wireless connections may be of low bandwidth or shared among multiple devices.
Traditional protocols such as TCP/IP are designed to deal with lossy and inconsistent connections by resending data. Even though the data flowing to or from any individual IoT device may be exceedingly small, it will grow quite large in aggregate IoT traffic. The inefficiencies of resending vast quantities of mostly individually unimportant data are clearly an unnecessary redundancy.