Chapter 3 Design Patterns for IoT 65
Solution
Using a distributed model where computing operations are spread across dierent environ-
ments can solve this problem. This gives benefits of heterogeneous deployment such as scalabil-
ity, more computing resources, on-demand resource enhancement, and more bandwidth. Also,
benefits of single environment deployment such as resource control, on-demand accessibility,
and closed environment setup.
Design Patterns for Infrastructure
These types of design patterns describe how various device technologies and networks can solve
physical infrastructure related problems for IoT. It also provides solutions for connectivity for
low power devices with wireless sensor networks.
WSN Access Point
Problem
In order for IoT devices to communicate with each other, they need to connect with each other
via a network. This network requires access points through which these devices can connect.
Solution
WSN stands for Wireless Sensor Network that allows various low power sensor nodes to connect
with each other. These sensors measure environmental conditions such as temperature, sound,
pollution levels, humidity, and wind. These WSN provide access points for these sensor nodes
to share data with each other.
6LoWPAN Edge Router
Problem
Many IoT deployments contain low power devices which are needed to communicate with
wireless infrastructure. This is problematic due to the power needed for devices to route IPV6
packets.
Solution
Low power devices need a dierent solution to communicate with each other. 6LoWPAN stands
for IPv6 over Low-Power Wireless Personal Area Networks. It routes IPv6 packages to lower
power networks by compressing a header.
Mesh Routing
Problem
Reliable communication among nodes and with the access point is essential for a successful IoT
deployment. If structured in a serial manner, upon failure of one of the nodes, the entire com-
munication may fail. Also, in another case, if structured in some other manner which requires
a particular node to connect with a particular node, then again failing on the dependent node
may cause in reliable communication.
Solution
This problem can be solved by creating a mesh structure so nodes are not dependent on a
particular node in the chain. Mesh structure provides connectivity in a direct, dynamic and
non-hierarchical manner. This type of structure oers reliability in data sharing as even if
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66 Internet of Things
one particular node fails, the communication can get diverted to other node in the mesh. This
removes the dependency on one particular node and allows every node to participate in relaying
information. As you can see this type of network is self-organized and self-configured, which
greatly reduces the maintenance and management tasks.
Behind NAT Connectivity
Problem
Every sensor node will require having a public IP address in order to get connected to the inter-
net. However, having this will increase the cost significantly as well as create a lot of security risk
by exposing these devices to the public network. In order to secure this device, we must monitor
and control trac which is a daunting task.
Solution
We can avoid having a public IP address for every sensor. All these sensors can work behind a
network where only one public IP is required and internally all these sensors can connect via
private IP addresses. This can be achieved by having a device, which can assign a public IP to the
computer and then private IPs to all other nodes. This process is known as Network Address
Translation (NAT).
Application Gateway
Problem
Security is an important aspect when setting up the wireless sensor network. Any third party
can target this network to get access to the nodes and control them. There is a need to make sure
the nodes are communicating in a safe manner.
Solution
A firewall proxy can provide the desired security, which can filter network application data.
These network applications can be Telnet, FTP (File Transfer Protocol), RTSP (Real Time
Streaming Protocol), and BitTorrent. This firewall proxy is known as Application Gateway,
which provides this required security at the highest level. This security can be achieved by
diverting the trac like a web page request or a file request through a proxy server that can
be diverted further to the main server. This proxy server has a public IP address which hides
the details of the main server as the outside world does not have access to it. The only access is
established by a proxy server.
M2M WAN
Problem
In IoT world, sensors must communicate with each other to perform required tasks. This must
happen without any human intervention. There should be a mechanism to make these devices
communicate.
Solution
Wireless communication has opened up a door of possibilities for these sensors to communicate
with each other. This node-to-node communication is achievable by M2M WAN (Machine-to-
machine Wireless Access Network) to exchange data and communicate without human inter-
vention. Some examples of this type of communication are sending an alert to all the doctors in
case a patient’s vitals are falling down to some threshold.
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