But true peer-to-peer communication isn't perfect democracy
– it's senseless cacophony. In the IoT, devices at the edge of the network have
no need to be connected with other devices at the edge of the network – there
is zero value in the information. These devices have simple needs to speak and
hear: sharing a few bytes of data per
hour on bearing temperature and fuel supply for a diesel generator,
perhaps. Therefore, burdening them with protocol stacks, processing, and memory
to allow true peer-to-peer networking is a complete waste of resources and
creates more risk of failures, management and configuration errors, and
hacking.
Having said that, there is obviously a need to transport the
data destined to or originating from these edge devices. The desired
breakthrough for a truly universal IoT is using increasing degrees of
intelligence and networking capability to mange that transportation of data.
Conceptually, a very simple three-level model will suffice.
At the edge of the network are simple Devices.
They transmit or receive their small amounts of data in a variety of ways:
wirelessly over any number of protocols, via power line networking, or by being
directly connected to a higher level device. These edge devices simply
"chirp" their bits of data or listen for chirps directed toward them
(and how are these addressed, you might ask – we'll get there in a later blog
post).
Note that I've said nothing about error-checking, routing,
higher-level addressing or anything of the sort. That's because none of these
are needed. Edge devices (Level I, if you will) are fairly mindless
"worker bees" existing on a minimum of data flow. This will suffice
for the overwhelming majority of
devices connected to the IoT*.
The emphasis in the last sentence above is a key point. Much
of what has been written about the IoT assumes an IP stack in every
refrigerator, parking meter, and fluid valve. Why? It's obvious that these
devices won't need the decades of built-up network protocol detritus encoded in
TCP/IP. We all must free our thinking from our personal experience of the
networking of computers, Smartphones and human users to address the much
simpler needs of the myriad devices at the edge of the IoT.
So if the end devices aren't capable of protocol
intelligence, it must reside somewhere. And the major elements of that
somewhere are the Level II Propagator nodes.
These are technologically a bit more like the networking equipment with which
we are all familiar, but they operate in a different way. Propagators listen
for data "chirping" from any device. Based on a simple set of rules
regarding the "arrow" of transmission (toward devices or away from
devices), propagator nodes decide how to broadcast these chirps to other
propagator nodes or to the higher-level Integrator
device I'll discuss in a moment.
In order to scale to the immense size of the Internet of
Things, these propagator nodes must be capable of a great deal of
discovery and self-organization. They will recognize other propagator nodes
within range, set up simple routing tables of adjacencies, and discover likely
paths to the appropriate integrators. I've solved this sort of problem before
with wireless mesh networking and although the topology algorithms are complex,
the amount of data exchange needed is small.
One of the important capabilities of propagator nodes will
be their ability to prune and optimize broadcasts. Chirps passing from-and-to
end devices may be combined with other traffic and forwarded in the general
direction of their transmission "arrow". In my view of the IoT,
propagators are the closest thing to the traditional idea of peer-to-peer
networking, but they are providing this networking on behalf of devices and
integrators at levels "above" and "below" themselves. Any
of the standard networking protocols may be used, and propagator nodes will
perform important translation functions between different networks (power line
or Bluetooth to ZigBee or WiFi, for example).
Integrator functions are where the chirps from hundreds to
millions of devices are analyzed and acted upon. Integrator functions also send
their own chirps to get information or set values at devices – of course these
chirps' transmission arrow is pointed toward devices. Integrator functions may
also incorporate a variety of inputs, from big data to social networking trends
and "Likes" to weather reports.
Integrator functions are the human interface to the IoT. As
such, they will be built to reduce the unfathomably large amounts of data
collected over a period of time to a simple set of alarms, exceptions, and
other reports for consumption by humans. In the other direction, they will be
used to manage the IoT by biasing devices to operate within certain desired
parameters.
Using simple concepts such as "cluster" and
"avoid", integrated scheduling and decision-making processes within
the integrator functions will allow much of the IoT to operate transparently
and without human intervention. One integrator function might be needed for an
average household, operating on a Smartphone, computer, or home entertainment
device. Or the integrator function could be scaled up to a huge global
enterprise, tracking and managing energy usage across a corporation, for
example.
When it comes to actually packaging and delivering products,
some physical devices will certainly be combinations of functions. Propagator
nodes combined with one or more end devices certainly make sense, as will other
combinations. But the important concept here is to replace the idea of
peer-to-peer for everything with a graduated amount of networking delivered as
needed and where needed. In the Internet of Things, we need a division of labor
(like ant and bee colonies) so that devices with not much to say or hear receive
only the amount of networking they need and no more.
Next time, we'll talk about the communications architecture
for the IoT in more detail and why the needs of the crowd are different from the needs of the cloud.
*Yes, there will be a relatively small number (still
billions and billions) of more-sophisticated devices connected to the IoT. But
these will connect with good ol' IPv6, as the investment of a protocol stack is
worth it.
