Lecture 3 - Communcation Models

Question 1

What are the IoT Requirements for Various Applications

Answer 1

Reliability
Latency
Mobility
Security
Power
Protocol Message Size
Frequency of Interactions

Question 2

What is the Relationship between Capacity and Bandwidth (Hz)

Answer 2

*The Nyquist formula provides a relationship between capacity and bandwidth under idealized conditions where noise is not considered.
* C(bps) = 2B * log(base2) *M (Nyquist)
* C is the capacity in bits per second, B is the frequency bandwidth in Hertz, and M is the number of levels a single symbol can take on.

Question 3

What is Device-to-Cloud communication

Answer 3

IOT device connects firstly to an internet cloud service like an application service provider to exchange data and control message traffic

Question 4

Communiucation Models - Device-to-Cloud Communications: Nest Learning Thermostat,

Answer 4

• In the case of the Nest Learning Thermostat, the device transmits data to a cloud database where the data can be used to analyze home energy consumption.
• Further, this cloud connection enables the user to obtain remote access to their thermostat via a smart phone or Web interface, and it also supports software updates to the thermostat.
• Frequently, the device and cloud service are from the same vendor.
• If proprietary data protocols are used between the device and the cloud service, the device owner or user may be tied to a specific cloud service, limiting or preventing the use of alternative service providers. This is commonly referred to as “vendor lock-in’’

Question 5

Communiucation Models - Device-to-Gateway Model: Transport Layer Security

Answer 5

• Transport Layer Security (TLS) is a cryptographic protocol designed to provide communications security over a computer network. The protocol is widely used in applications such as email, instant messaging, and voice over IP, but its use in securing HTTPS remains the most publicly visible.

Question 6

Communiucation Models - Device-to-Gateway Model: Datagram Transport Layer Security

Answer 6

• Datagram Transport Layer Security (DTLS) is a communications protocol providing security to datagram based applications

Question 7

Communiucation Models - Device-to-Gateway Model

Answer 7

*In the device-to-gateway model, or more typically, the device-to-application-layer gateway (ALG) model, the IoT device connects through an ALG service as a conduit to reach a cloud service.
* This means that there is application software operating on a local gateway device, which acts as an intermediary between the device and the cloud service and provides security and other functionality such as data or protocol translation
* Several forms of this model are found in consumer devices. In many cases, the local gateway device is a smart phone running an app to communicate with a device and relay data to a cloud service.

Question 8

Communiucation Models - Device-to-Gateway Model; What is it used for?

Answer 8

• This is often the model employed with popular consumer items like personal fitness trackers. These devices do not have the native ability to connect directly to a cloud service, so they frequently rely on smart phone app software to serve as an intermediary gateway to connect the fitness device to the cloud
• The other form of this device-to-gateway model is the emergence of “hub” devices in home automation applications.
• These are devices that serve as a local gateway between individual IoT devices and a cloud service, but they can also bridge the interoperability gap between devices themselves.

Question 9

Communiucation Models - Back-End Data-Sharing Model

Answer 9

• Back-End Data-Sharing essentially extends the single device-to-cloud communication model so that IoT devices and sensor data can be accessed by authorized third parties.
• Under this model, users can export and analyze smart object data from a cloud service in combination with data from other sources and further send it to other services for aggregation and analysis.

Question 10

What is *Constrained Application Protocol (CoAP) (under Back-End Data Sharing)

Answer 10

*Constrained Application Protocol (CoAP) is an Internet Application Protocol for constrained devices (defined in RFC 7228). It enables those constrained devices to communicate with the wider Internet using similar protocols.
*The Internet Protocol Suite is increasingly used on small devices with severe constraints on power, memory, and processing resources, creating constrained-node networks.

Question 11

What is OAuth (under Back-End Data Sharing)

Answer 11

• OAuth is an open standard for access delegation, commonly used as a way for Internet users to grant websites or applications access to their information on other websites but without giving them the passwords
• This mechanism is used by companies such as Google, Facebook, Microsoft and Twitter to permit the users to share information about their accounts with third party applications or websites.