A Practical Guide to Using the Industrial Internet Connectivity Framework
4. Must your dataflow cross firewalls that
you do not control?
5. Is
there
no
device-to-device
communication?
fact, runs on the device itself, providing
an
intuitive
configuration
and
management interface. Browsers can
simply connect directly to the device,
giving full access to advanced visual
capabilities. This is limited to local
connections, so another common
configuration is to combine this with the
above by having both the device and the
user connect to a cloud-based HTTP
service. This allows easy remote access
to the device.
3. RESTful HTTP is an approach, not a
standard with an official type system.
However, most web systems use text
encodings like JSON or XML. Text
encoding is not fast so response speeds
may satisfy humans, but not fast
machines. Binary systems like Google
Protocol Buffers (Protobuf) and the new
HTTP/2 standard offer more efficiency,
but are not yet widely used. HTTP runs
over TCP, which does not deliver low
latency.
4. Because all websites offer HTTP services,
most IT firewalls allow connections to
HTTP’s default port (80). Deep packet
inspection systems will likely accept
HTTP. Thus, using HTTP on port 80 is
usually the easiest way to traverse
firewalls without special configuration.
5. RESTful HTTP requires that all devices
connect to a server. While multiple
devices may interact through that server
or share a database, applications that
share data between devices are rare.
Three “yes” answers indicate you will likely
be best off with RESTful HTTP. The reasons:
1. RESTful HTTP fundamentally makes it
easy to connect a field device to a web
service. REST is the most widespread way
to build web services, enabling copious
offerings to help developers. For
instance, the DreamFactory open source
project automatically creates APIs from
most any database, thus enabling a
centralized data-centric approach.
While most applications use hypertext to
present a linked view of a web page to a
user, this paradigm is also similar for
many IIoT “monitoring” applications.
These applications are similar to smart-
phone apps, except there is no human
user. Instead of a phone, the end entity
is a “thing,” typically a single device.
From a connectivity perspective, the
things usually have only a single
connection to an IoT platform. This
category includes most of the
“consumer” IoT, including thermostats,
wearables and smart home locks.
The
most
important
industrial
applications
are
“predictive
maintenance” systems that upload
device data to the cloud. Cloud systems
then analyze the data to predict when a
part may fail, allowing proactive repair.
2. HTTP is the most common way to serve
information to human users. While most
think of HTTP servers as living in the
cloud with clients on the edge, this often
is not the case in IoT. The server often, in
MQTT
MQTT is a very simple protocol designed
mostly for the “data collection” use case. It
does not qualify as a “core connectivity
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September 2017