This paper is a broad, high-level technical overview explaining the various technology aspects of Machine-to-Machine (M2M) and Internet of Things (IoT), how they relate to one another, and how they differ. This paper is a little dated now, as it was created in 2014, before IoT was the term that really won out :); but I think the content still holds. This whole effort, and M2I-SF, later became the IoT Security Initiative. You can find newer better content there - www.iotsi.org

1. Making Sense of
M2M and IoT
MIKE HORTON

2. www.m2isf.com2
Making Sense of M2M and IoT
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Making Sense of M2M and IoT
The market for M2M and IoT is set to explode
soon by all industry accounts. No need to rehash
and beat the drum of such prognostications, but
this does seem likely to happen.
This paper aims to provide a midlevel,
comprehensive, and somewhat nontechnical
set of answers to these questions as well as a
technical view of the entire associated landscape
involved with M2M and IoT systems. The
reader should be able to better understand
the technology underpinnings as well as future
associated elements associated with these
system solutions.
Before we discuss terms such as machine-to-
machine (M2M) and Internet-of-Things (IoT), it is
first necessary to have a decent understanding
of embedded systems and how they relate to
your computer at home and your mobile phone.
Embedded systems/devices differ from the
classic understanding of a personal computer
(PC) in that all components needed for the
system’s core operation are soldered, or
“embedded,” directly onto the device’s circuit
board(s), and for all intents and purposes
sealed in a casing enclosure never to be
changed or altered.
Embedded systems like the PCs we are more
familiar with have smarts in the form of
processors and microcontrollers; software for
base application functionality and sometimes
operating systems; input and output in the
form of screens, keypads, cables, and wireless
modems; and storage in the form of Read
Only Memory (ROM), Random Access Memory
(RAM), and flash RAM.
Y
ou have likely seen these acronyms and terms splashed around technology
media and marketing materials with increasing frequency: M2M, IoT, IoE,
SCADA, WoT, Telematics, Connected World, and Industrial Internet. What
exactly do they mean? Are they the same thing? One-offs created by different
companies in the connected Internet space? Are they all really just mobile
computing or embedded systems with associated network and cloud services?
WELCOME

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Making Sense of M2M and IoT
Mobile smartphones, for example, are embedded
systems, though they have more or less become
their own class of personal computing device
given the amount of user interaction, dynamic
functionality and customization supported and
the raw horsepower they now have. They are
now truly smartphones compared with those
from earlier days.
What differentiates embedded systems from
one another are their levels of architectural
complexity, computing horsepower, and
operating platform. This holds true whether
you are considering a mobile handset, your
car’s computer control system, or your LCD TV,
as just a few examples.
What distinguishes an embedded system
from a PC more or less comes down to three
primary design characteristics: firmware, system
interaction, and system modification.
First, an embedded system uses a firmware
image of the operating platform that is written
to static ROM. This firmware image will contain
all the software the system needs to operate and
perform its function, but this firmware image is
not meant to be readily user modifiable. On the
other hand, the PC is much more dynamic in this
regard, as the operating system can be installed
easily in addition to many third-party applications
built to run on that operating platform.
What distinguishes an embedded system from a PC more or less
comes down to three primary design characteristics: firmware,
system interaction, and system modification.

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Making Sense of M2M and IoT
Second, the extent of direct user interaction
with each one is different. With a PC, the user
has a screen and a keyboard to directly interact
with the operating platform and applications,
whether through a rich graphical or command
line user interface. Alternately, an embedded
system will usually not have this at all, and if
it does, it will often be a minimal, and even
secondary, advanced interaction capability.
The last differentiating characteristic is the
amount of direct hardware customization
allowed. A PC was designed to be modified
and customized—from the software to the
internal boards, the case, and the chips
themselves. An embedded system is designed
and manufactured to be more or less set in
construction, with an enclosure and design
sealed, or at least not readily supporting internal
modification by the user.
These differences are not hard rules of
distinction, as the lines are blurred in various
ways with computing systems, but they are
important to consider.
M2M = Embedded
A device considered part of an M2M system
will be the classic embedded system as was
discussed above; and an embedded device that
is “field deployed” as compared with a server in
a data center.
What begins to differentiate the device as
machine-to-machine is that the embedded
system often communicates with another
embedded system as a peer or gateway before
backhauling to a server somewhere else. Put
simply, take an embedded system and put a
serial, Ethernet, WIFI, ZigBee, cellular, or other
link on it so that it can talk intelligently with
another embedded system, but without any
user interfaces, and you have an M2M system,
hence the machine-to-machine term.
Another way to think about M2M is to imagine
that the machines are doing the talking to other
machines doing the listening. Sometimes, this
is between other device nodes, and sometimes
this is communicating directly back to a server
receiving the data. And they are doing so as
part a complete system designed for a specific
function or operation; their primary roles are
not defined as computing systems composed of
people-interacting interfaces and functions.

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Making Sense of M2M and IoT
Figure 1: This logical breakout of M2M/IoT technology and systems depicts the possible core components
of the embedded device as well as the possible communications interconnects and back-end services
interactions often involved with a complete system solution.
m2m technology surface logical breakout

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Making Sense of M2M and IoT
In its truest form, an M2M device is an
embedded system that communicates
symbiotically with another embedded system
or systems during its primary functions. Think
small devices in a mesh network that do not
have any sort of user interface or keyboard, etc.
M2M systems are often deriving data from
directly (same board, enclosure) or indirectly
attached sensors and actuators of varying types
as part of their system purpose. This data
will frequently determine and affect different
environmental, operational, and physical states
of the device and system as a whole.
This state data, more formally called telemetry
data, is received in the embedded M2M
controller and then communicated to other
similar control systems in a personal or local
area network (PAN/LAN). This state data could
then be communicated longer distances as
required to more powerful computing systems
over Wide Area Networks (WAN) using wired or
wireless links.
M2M systems may also communicate either
directly among themselves, directly to back-end
servers, or through a gateway node for the LAN/
WAN backhaul connection.
Although M2M systems use wired connections as
well as different forms of wireless connection for
both local and wide area connections, they are
becoming increasingly associated with a cellular
connection. This is particularly true for gateway-
class embedded devices that afford more robust
processing and have directly connected or
rechargeable power. These cellular connections
Figure 2: The diagram depicts a typical logical connection chain, from device to back-end servers and the
primary elements of those connections to be considered at each leg.
m2M/IOT end-to-end primary system components

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Making Sense of M2M and IoT
can act as either a primary or a secondary link-
point to a wide area network.
M2M System Uses and Markets
M2M systems serve many different roles
today, which have been further enabled by the
expanding capabilities of cellular and satellite
communications. Roles that were previously
more difficult to serve because of their
remoteness are now more easily connected.
This relationship, coupled with the dominance of
the WAN and Internet, has continued to propel
M2M on an ever-steeper growth trajectory.
As an example, a list of common M2M uses for
consideration includes the following:
• Positioning and tracking vehicles
and goods
• Automated system malfunction alerts
• Collection and transmission of in-field
telematics data
• Facility intrusion alerting and monitoring
• Monitoring and management of
industrial systems
• Notification and reporting of vending/
kiosk machine operation
M2M devices actively serve a broad range of
industries today. The list below identifies some
of the primary industry segments that M2M is
actively used in or seen to be moving into more
heavily in the future:
• Automotive
• Banking & Payment
• Consumer Electronics
• Field Service
• Government & Military
• Healthcare
• Home Automation
• Industrial Control Systems
• Remote Monitoring
• Remote Security
• Supply Chain
• Utilities & Smart Metering

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Making Sense of M2M and IoT
M2M Communications Architectures
An M2M end-node device can be classified
into three primary categories: sensor/actuator,
control system, and gateway. Each of these
M2M device types would have some sort of
communications module integrated. The
communication module could be wireless,
wired, or both as well as cellular-based
or not, depending on local and wide area
communications needs. A complete M2M
solution could also utilize all three types
integrated together as a single “system.”
Both stand-alone and integrated
Figure 3: This image shows the possible communication technologies that could be considered and utilized at
the different “legs” of an end-to-end M2M system. The dotted boxes represent services and connections that
may not exist in a solution; see figure 4 for more relevant connection examples.
potential m2M/IOT communication technology applications

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Making Sense of M2M and IoT
communications modules exist for the various
types of radio frequency (RF) communication
needs. The communications module in a
device will often integrate either cellular or
Personal Area Network/Local Area Network
(PAN/LAN) RF and sometimes, though rarely,
both. This is beginning to change, however,
as chipmakers are designing more robust and
flexible communications chips. Still, the “bill of
materials” (or BOM) cost considerations are king.
Cellular Connectivity
M2M devices that utilize a cellular modem for
communications operate in the same way as
any other mobile handset. The M2M device’s
operating system will use the cellular modem,
which will establish and maintain a cellular
connection—GSM, UMTS, or LTE in the Americas
for the most part—to a cellular tower near
where the device is operating. That cellular
tower will communicate back to a mobile
switching center and into a network data core
for associated accounting, cost, access, and
service functions.
The M2M device will be associated with a
cellular network and a business customer as
the owner of the cellular account, just like a
consumer mobile handset is today. And like
mobile handsets, an M2M device will also use
a particular cellular access point name (APN)
for the data connection, though for an M2M
device it may be using a custom APN gateway
associated with that business customer.
Where things diverge a little is where the data
connection goes once it leaves the carrier’s (or
MVNO’s) cellular data core.
The M2M device will be associated with a cellular network and
a business customer as the owner of the cellular account, just
like a consumer mobile handset is today. “

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Making Sense of M2M and IoT
From a mobile carrier’s point of view, the tip
of the spear in the M2M devices space is the
Subscriber Identity Module (SIM) card, or more
accurately, the Universal Integrated Circuit Card
(UICC). This is also in terms of cellular GSM
networks, the global dominant, as apposed to
CDMA cellular technology.
The UICC, along with the cellular modem
module, is what provides the cellular link of the
M2M device that connects a back-end server
system in most cases. Such connections are
either across the Internet or a dedicated circuit
connection if the service being connected is “off-
carrier” at a corporate Enterprise, for example.
In both instances, these connections exit the
cellular provider’s data core to then connect
to an M2M provider’s back-end servers. These
back-end server systems then perform the data
collection and processing for other downstream
systems, or users.
To help manage and facilitate communications
for all those M2M cellular modems, a back-
end central command is often present as
well as a control system. This command and
control system is a software-as-a-service
type of web portal, either partnered with
or operated by the mobile carrier. Such a
service would help provision, manage, and bill
M2M device communications to the Original
Equipment Manufacturer (OEM) that sells
the M2M product to the end user, which is
either a consumer or a business. Beyond this,
it also helps connect and coordinate device
communication to any other Enterprise-based
network services of the customer’s.
The Use of Cellular in M2M
It does not seem a foregone conclucion that all
M2M end-node devices will be predominantly
cellular based for their communications. It is
just not a practical communication means for all
use cases given the low power needs and costs
of many of these end-node operating scenarios.
For example, cellular is data and a power-hungry
relative to the power and communication
deployment needs of a small M2M sensor node.
That is on the product designer/OEM side of

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Making Sense of M2M and IoT
concerns. Then there is the issue of all that
signaling traffic between a cellular modem and
the base station, which is already becoming
a concern with current mobile operations, let
alone adding x-million more communicating
nodes to cell sites; small-cell or not, all of which
seems impractical until at least 2018/2020.
Efforts are currently under way in the European
Telecommunications Standards Institute (ETSI)
and 3GPP standards bodies to establish new
cellular communications models specific to the
needs of M2M—device makers and carriers.
Such a move could certainly help if not solve
part of the issue longer term. Even then,
though, we will have to see how these efforts
unfold and how possible and likely adoption is in
the face of other new technology solutions that
might present themselves.
Regardless, from an “operating requirements”
and “bill of materials” standpoint, designing a
2G/3G/4G modem into any small device will
take serious consideration. Power and other
issues rise dramatically as you move from
2G to 4G LTE modem use currently. Other
questions regarding the longevity of the product
designers/OEMs product relative to the longevity
of the 2G networks come up as well. Many
advocate shutting down 2G capabilities among
cellular operators, but given these factors and
the drive for M2M, such a move would appear
unlikely for the near term.
If it is a specialty consumer device in question
that could support recharging capabilities or is
always attached to an electric current source,
then the use of cellular directly (2G/3G/4G)
in these endpoints is quite feasible. An
implementation such as a vehicle, which could
The M2M device will be associated with a cellular network and
a business customer as the owner of the cellular account, just
like a consumer mobile handset is today. “

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Making Sense of M2M and IoT
support both large batteries and recharging,
is a perfect example as would be a plugged-in
vending machine.
The likely scenario is that cellular connections
will be mainly applied to M2M device gateways
and end-node devices that can support a
stable and consistent power supply given
their deployment scenario. In-home units?
No problem. User carried? Not as much of a
problem, but maybe less likely still. Remote,
small, off-grid sensor types? Unlikely to go
cellular until better M2M-friendly cellular
standards appear in the market. In these
Figure 4: This image depicts the various logical connection possibilities in M2M and IoT systems, each row
being a possible system connection pattern.
EXAMPLE m2M/IOT END-TO-END SYSTEM CONNECTION SCENARIOS

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Making Sense of M2M and IoT
examples then, other LAN/PAN/MAN RF
technologies, such as white space bandwidth-
oriented Weightless or SIGFOX, ZigBee, and
Bluetooth, or other new emerging ones will
continue to grow in this gap.
What About Vehicle Telematics?
Telematics is another M2M-associated term
that is often heard but not well understood.
Essentially, the term “telematics” refers to the
combination of computer processing system
capabilities together with telecommunications
capability in a single system for the purpose
of transmitting data and commands to and
from a remote processing system. Telematics
is most commonly associated with wireless
communications, if not solely. The term
“vehicle telematics” is merely the more
commonly understood use of telematics
—in vehicles.
Telematics is not to be confused with the term
telemetry, which is the remote measurement of
data from an origin point to a remote processing
point. By these definitions, it should also be
clear that telematics systems could and do
process telemetry data.
Telematics is a slightly “newer” term from the mid-
1970s, while telemetry is a much older concept.
Wired telemetry use is at least several
decades old, and cellular services have also
been commonly used to transmit telemetry
data over the years, with it now the common
associated means.
the term “telematics” refers to the combination of computer
processing system capabilities together with telecommunications
capability in a single system.”

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Making Sense of M2M and IoT
To summarize: telematics, especially vehicle
telematics, could be seen as an interchangeable
term with the more modern M2M or with
Internet of Things as in-vehicle technology
matures. Some feel we should retire the term
“telematics” to history, using M2M exclusively,
as M2M is the newer buzzword and a much
catchier acronym and phrase. Nevertheless,
telemetry in and of itself is still very applicable
for both M2M and IoT type systems.
M2M in Relation to SCADA
SCADA, which stands for Supervisory Control
and Data Acquisition, is a class of control
system software and hardware components
used in industrial automation. SCADA systems
commonly process and control the transfer
of data and commands to gauges, sensors,
and actuators within plants and remote field
equipment locations.
SCADA systems are primarily used in such
operations as oil and gas refineries, power
plants, water treatment facilities, and other
plants related to “utilities.” These systems are
often characterized as critical infrastructure,
but they can also be seen in corporate
industrial Heating, Ventilation, and Air
Conditioning (HVAC) operations.
Similar to our discussion of M2M systems, SCADA
also consists of embedded systems of varying
capability and functionality communicating with
like units as well as back-end servers in a classically
closed proprietary system. Accordingly, SCADA
systems can be considered as nothing more
than a specialized derivative class of M2M with
perhaps a dash of Internet of Things being added
to the mix as of late, which is now sometimes also
termed the Industrial Internet among others.
M2M in Relation to The
Internet of Things, etc.
There is often quite a bit of understandable
confusion concerning the difference between
M2M and the Internet of Things, often shown as
the acronym IoT.
There is also now the Internet of Everything (IoE),
which is basically the same thing, and then the
Web of Things (WoT), which is an offshoot to entail
the use of web services and protocols for the IoT/
IoE, which seems to be implied somewhat.

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Making Sense of M2M and IoT
Figure 5: The image above shows the associative
correlation between the various technology realms
and the degree to which M2M and IoT relate to and
overlap them.
To try and summarize this in more specific
terms, M2M is the automated exchange of
telemetry, operational, and other command
and control information between machines;
predominantly sensor-like, and non-GUI
embedded systems; and often additionally
to servers and services where humans make
broader use of the data. M2M devices can
communicate with each other and back-end
systems in a wired, RF wireless, cellular, or
satellite means.
M2M devices also operate in a variety of
network topologies, can utilize an M2M gateway
device, or not, can communicate via layer 2 or 3,
and be static or dynamically IP addressed.
The “Internet of Things” is broader umbrella
terminology that refers to the merging of
previously static objects (e.g., refrigerator, car)
into an Internet context and then driven by
human interaction with the object in a broader
sense given an “Internet services capability”
overlay of sorts. In contrast to this, M2M is
machine interaction driven.
Internet of Things can involve M2M systems
but is not one in the same. Conversely, M2M
does not need an Internet of Things “human
interaction” context or Internet connectivity to
function as an M2M system.
Internet of Things systems are more classically
aligned with common Internet and web
The “Internet of Things” is broader umbrella terminology
that refers to the merging of previously static objects (e.g.,
refrigerator, car) into an Internet context.”

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Making Sense of M2M and IoT
technologies and communications, though this
is beginning to change. IoT could be thought of
as the “glitzier” Internet side of M2M that allows
more consumer user interaction with the system.
Although the terms are often used
interchangeably, subtle distinctions allow
for hazy intersection and overlap. Figure 5
attempts to show the relationship and overlap
of the various associated terms.
Still Confused?
If you’re still completely confused about all
these acronyms and fuzzy definitions, know
that you are not alone. This space will continue
to shake out and become further defined.
This paper was an attempt to explain these
terms and their relationships as this author
understands and views them. It is hoped this
information will provide some better context
and understanding for you.
Essentially, though, M2M and IoT devices are
all predominantly embedded systems with
some featuring more user interaction and user
interface conveniences than others. At this
point, it seems that the term IoT is winning out
in the consumer media space over M2M and
gaining ground in the OEM space as well. It
could very well be that IoT wins out as the de
facto term. Both M2M and IoT could continue
on as well. Or maybe a new term will arise to
cover both. Machine-to-Internet (M2I) anyone?
Regardless of the name, however, as we further
consider all the various technology, protocol,
security, and privacy aspects of these systems,
just be sure to keep in mind that all these
embedded systems will have generally the same
technologies, issues, threats, and concerns.
From M2M to IoT to SCADA, they are, in
essence, the same types of embedded systems
communicating with other embedded systems
and to back-end network services.

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Making Sense of M2M and IoT