1. WSN- Wireless Sensor Network
Data link layer application based
projects
By :-
Abhinav Ashish
Manager , NETRA
NTPC Ltd
Mail ID: abhinavashish@ntpc.co.in
3. Open Source Interconnects
S.
No.
Layer Name Functionality
1 Layer 1:
Physical Layer
Electrical and Physical systems of the Network. Eg. Cable type, Radio Frequency Link , Pin layout, Voltages and other
physical requirements.
2 Layer 2 :
Data Link Layer
Provides node-to-node data transfer (b/w two directly connected node) and also handles error correction from the
Physical Layer. This has two sub-layers- Media Access Control (MAC) Layer and the Logical Link Control (LLC) Layer.
Most switches operate at layer-2.
3 Layer 3 :
Network Layer
Most router functionality are taken care of in this layer. It is responsible for packet forwarding including routing
through different routers. This helps in selection of the optimal route out of the several possibilities (may be in
millions). Some switches also operate at Layer 3 in order to support virtual LANs that may span more than one switch
subnet, which requires routing capabilities.
4 Layer 4 :
Transport Layer
It deals with data transfer between end systems and hosts. It deals with questions like How much data to send, at
what rate, where it goes etc. The best known example of the Transport Layer is the Transmission Control Protocol
(TCP), which is built on top of the Internet Protocol (IP), commonly known as TCP/IP. TCP and UDP port numbers work
at Layer 4, while IP addresses work at Layer 3, the Network Layer.
5 Layer 5 :
Session Layer
It creates session to facilitate the talk between any two devices on network. Functions at this layer involve setup,
coordination (how long should a system wait for a response, for example) and termination between the applications at
each end of the session.
6 Layer 6 :
Presentation Layer
The Presentation Layer represents the area that is independent of data representation at the application layer. In
general, it represents the preparation or translation of application format to network format, or from network
formatting to application format. In other words, the layer “presents” data for the application or the network. A good
example of this is encryption and decryption of data for secure transmission; this happens at Layer 6.
7 Layer 7:
Application Layer
The Application Layer in the OSI model is the layer that is the “closest to the end user”. It receives information directly
from users and displays incoming data to the user. Oddly enough, applications themselves do not reside at the
application layer. Instead the layer facilitates communication through lower layers in order to establish connections
with applications at the other end. Web browsers (Google Chrome, Firefox, Safari, etc.) TelNet, and FTP, are examples
of communications that rely on Layer 7.
4. Samsung’s SmartThings, a Smart Homes
Network
Nest devices connect via Wi-Fi or through BLE
(Bluetooth Low Energy), and each device
thereby become a node on the homeowners
own IoT. The thermostat can then be
controlled via a free Android or Apple app.
The app also warns the homeowner if there is
any problem on the system.
It starts with the network, established with a SmartThings
Hub, with connectivity is achieved via ZigBee, Z-Wave, Cloud-
to-Cloud, LAN, ZigBee3. Alternatively, Samsungs SmartThings
Wifi can be utilized. Depending on the configuration, smart
home devices connected to the network can be controlled by
the SmartThings app for iPhone and Android, or via Amazon
Alexa or Google Assistant.
SmartThings Wi-Fi provides you a mesh Wi-Fi network with
extended range. In my previous article on new mesh
networking products in connected devices, I explore the
range-extending properties of this powerful type of network.
If you're curious about the hardware, check out
our teardown of the SmartThings water leak sensor.
Integrating IoT hazard sensors
onto a smart home network
presents the user with a variety of
pathways. There are individual
sensors, and there are also sensors
with built-in connectivity. Added
security is available, or the user
can rely on existing protections.
There are also dedicated networks
devoted specifically to the smart
home.
Of course, with 5G just around the
corner, there are sure to be
surprises in store for the evolution
of IoT hazard sensors and the
networks they rely on
Secure IoT Connectivity for the Home
These days, smart users take strong protections
against our laptops and internet accounts being
hacked. But we neglect to protect an even more
critical and vulnerable asset—our homes.
With the rise of IoT-connected smart homes, this can
be a tragic omission. Strong security features that
protect against potential hacking and other threats
are a must when it comes to wireless IoT devices that
automate and control their environment.
Samsung’s Exynos I T100 is designed with security in
mind. The device is equipped with a separate
Security Sub-System (SSS) hardware block for data
encryption and a Physical Unclonable Function (PUF)
that creates a unique identity for each chipset.
The device supports BLE 5.0 and Zigbee 3.0, two of
today’s major short-range communication protocols.
Detecting Dangerous Gases
The ZMOD4410 gas sensor module from IDT is
designed for detecting total volatile organic
compounds (TVOC) and monitoring indoor air quality
(IAQ), all of which can be read via an I2C interface.
The module’s sense element consists of a heater
element on a Si-based MEMS structure and a metal
oxide (MOx) chemiresistor. The signal conditioner
controls the sensor temperature and measures the
MOx conductivity, which is a function of the gas
concentration.
It is housed in a 12-pin LGA assembly (3.0 x 3.0 x 0.7
mm) that consists of a gas-sense element and a
CMOS signal-conditioning IC.
Smart Home Roundup: IoT Sensors and Wireless Networks for Hazard Detection
5. The authors proposed six transmissions algorithms by increasing the
levels of knowledge:
1. First Contact (FC)
2. Minimum Expected Delay (MED)
3. Earliest Delivery (ED)
4. Earliest Delivery with Local Queuing (EDLQ)
5. Earliest Delivery with All Queuing (EDAQ)
6. Linear Program (LP)
Study and development of wireless sensor network
architecture tolerant to delays
6. Classification and comparison of DTN routing protocols
TABLE 2.1: Names list of DTN routing protocols.
Abbreviations Protocol names References
• HEC Hybrid Erasure Coding [31]
• RAPID Resource Allocation Protocol [14, 13]
• LMR Link Metric Routing [56, 52]
• ER Epidemic Routing [17, 109]
• RC Relay Cast [68]
• TBF Tree Based Flooding [46]
• EBEC Estimation based Erasure Coding [72]
• SR Source Routing [100]
• PHR Per Hop Routing [55]
• PCR Per Contact Routing [55]
• HR Hierarchical Routing [77, 66]
• GR Gradient Routing [113, 91]
• LBR Location Based Routing [19]
• THR Two Hop Routing [56]
• DD Direct Delivery [56, 89]
• SW Spray and Wait [105, 62, 103]
• RUNES Reconfigurable Ubiquitous Networked [34, 35]
• Embedded Systems.
• FC First Contact. [56, 89]
• PRoPHET Probabilistic Routing Protocol using History [67, 73, 74]
of Encounters and Transitivity.
10. Performance metrics
We evaluate the performances of the six protocols according to four metrics:
1. Average latency: It represents the message delay from its creation to its
delivery to the destination node.
2. Buffer time: It is the average time that messages are stored in a buffer at each
node.
3. Delivery probability: It represents the number of successfully delivered
messages to the destination. It is defined as:
Delivery Prob = (1.0 * delivered messages) / created messages.
4. Overhead ratio: It is an assessment of the bandwidth efficiency. It is
interpreted as the number of created copies per delivered message.
That is the amount of replicas necessary to perform a successful delivery.
