Lecture #4 - Cloud vs Edge Technology/ Service Architectures

Question 1

What’s MQTT and what is it designed for?

Answer 1

MQTT (Message Queueing Telemetry Transport) is a lightweight, TCP/IP-based publish-subscribe network protocal that transports messages between devices.

It is designed for connections with remote locations where a “small code footprint” is required or the network bandwidth can be limited.

Question 2

What is OPC UA and what is it designed for?

Answer 2

Open Platform Communications Unified Architecture is a platform independent, service-oriented, open and secure communications architecture.

It is designed to enable the interoperability of industrial
automation devices, systems, and software applications
from different vendors. OPC UA information model
defines the data encoding and format of the data
transported with various transport protocols.

Question 3

What does publish and subscribe mean?

Answer 3

1. Provides an alternative to the traditional client-server architecture.
2. Decouples client that sends the message (pub) to the client that receives the messages (sub)
3. Pub and sub never contact each other directly; dk each other exists.
4. Broker filters all incoming messages and distributes them correctly to the subscribers.

Question 4

What’s the difference between OPC DA vs OPC UA

Answer 4

OPC DA uses the windows platform. This is different to OPC UA, which has a client server system and is platform independent.

• The connection to server is with COM nad DCOM
• Client to server uses SOAP/TCP/IP

Question 5

What is the OPC UA companion specifications

Answer 5

Defined data point structures are specified for industry-specific applications and objects.

Question 6

What’s the difference between OPC UA and Companion Specifications in terms of standardisations?

Answer 6

OPC UA standardises the exchange of data with machines and systems, whereas, the Companion Specifications additionally standardise the data models for similar machines and systems.

Question 7

What does the OPC UA and Companion Specifications cause?

Answer 7

Leads to a significant simplification in networking according to the Industry 4.0, since machines from different manufacturers deliver and receive the same data structures.

Question 8

Why is industry not too fussy in terms of having good standardisaion.

Answer 8

The industry can’t be competitive and therefore, must have other features.

Question 9

Describe what a wildcard is

Question 10

Describe what the Quality of Service is

Answer 10

The description or measurement of the overall performance of a service, such as a computer network or a cloud computing service, particularly the performance seen by the users of the network.

Question 11

What is the CPPS Cloud Architecture

Question 12

Name and explain the four cloud-variants

Answer 12

1. Public
2. Hybrid
3. Private
4. Multi

Question 13

Name the three service architectures in CPPS

Answer 13

DT twins can be hosted in Cloud Systems; Infastructureaas, Platformaas, Softwareaas

Question 14

Explain what it means to subscribe to something

Answer 14

One can subscribe to the picture and gets a notice everytime a new picture gets uploaded.

Question 15

Write a piece of code that causes a topic and two sub-topics using MQTT

Answer 15

Machine_1/Engines/Engine_1