Lecture 10 (Service Oriented Architectures)

Question 1

How are Information Systems and Business Processes associated?

Answer 1

IS and BP are associated as Business processes deal with a lot of information that is stored and retrieved from Information Systems.

Any changes in the design of a IS decide what is possible in the Business process it is tightly coupled with.

Question 2

What is Tight Coupling and what are it’s disadvantages?

Answer 2

Tight coupling in a software context refers to a scenario where different modules or components of a system are highly dependent on each other. This means changes in one module often require changes in others. Some disadvantages of tight coupling include:
1. Less flexibility: changes in one place force you to make changes to other parts too
2. High maintanance: changes in one place have ripple affects
3. Limited reusability: Very context specific usage
4. Harder to test: since other components required as well

Question 3

What is IIS?

Answer 3

IIS stands for Inter-organisational Information System.
Adopt IS that facilitate the exchange of information between two or more organisations, whose ownership is shared by those organisations and that are tightly coupled with each organisationals own internal IS.

eg: SCM & CRM, Funda.nl

Question 4

What are the challenges with using IIS?

Answer 4

Challenges:
1. Which organisation has main responsibility?
2. How to deal with Institutional distance ?
3. How to implement IIS in many-to-many business relationships.

Question 5

What is Service Oriented Architecture (SOA) ?

Answer 5

Core idea -> to decouple business processes and information systems as well as different information systems.

Service -> refers to frequently executed business processes that can be invoked without the knowledge of underlying systems.

Question 6

What’s the SOA workflow ?

Answer 6

Service is created&raquo_space; Service is registered&raquo_space; Customer finds service&raquo_space; Customer understands the parameters of the service&raquo_space; Customer requests for the service&raquo_space; Service is provided to the customer

Question 7

What are the characteristics and limitations of SOA?

Answer 7

• Characteristics:
  
  • Loose coupling: allows modifications and adaptations to individual components with minimal impact to the overall architecture.
  • Reusability: Can repeatedly execute business functions that might be needed in different environments/stakeholders.
  • Control: Protocol allow to specific access for data, functionality and at what intensity and to whom.
• Limitations:
  
  • Services correspond to a set of repeated tasks
  • Services abstract from, but interact with same IS as before → challenges of maintaining IS not addressed.
  • Reliability → One part causes some other parts to stop functioning too.

Question 8

What is Enterprise Service Bus?

Answer 8

• Takes care of scheduling, sequencing to avoid tight coupling of services and information systems.
• Services are loosely coupled to the underlying technology (i.e information systems)

Question 9

What are “Services” ?

Answer 9

• Defined standalone units that combine data or functionalities from one IS to another.
• Frequently executed business functions
• Invoked without knowledge to underlying IS
• Separate interface from implementation

Question 10

What is “Microservice architecture” ?

Answer 10

• Core idea:
  
  • Rebuilding organisations IS’s from scratch
  • Provides fine-grained functionality that can be requested in a standardised manner.
  • Microservice → It’s own technology stack
  • Internal & External customers request data through them

Question 11

What are the characteristics and limitations of Microservices?

Answer 11

• Characteristics:
  
  • Similar to SOA in some ways
  • Atomisation → Single piece of complete functionality (one service → one task)
  • Distribution → Application functionality in business processes and data are distributed across many services.
  • Independence → Services can be deployed/changes without affecting others as each has its own technology stack.
  • Cohesion → Service call upon other services to deliver functionality.
• Limitations:
  
  • Dependence & Complexity → Can increase latency
  • Communications → Good or Bad
  • Duplication → Code and data across multiple services
  • Overspecialisation → Makes it difficult for developers over different teams.

Question 12

What is the “Spotify Model” ?

Answer 12

Agile: Small team, short-cycle, iterative and continuous development

DevOps: Teams responsible for development and operations

The model means braking down a big system into smaller systems that each do their own part. They work together but are independent.

Question 13

Application/Solution for tight coupling ****?????

Answer 13

Creating custom integrations between different IS models makes is possible for CRM and IMS to talk and exchange data with each other.

Disadvantages:
1. Requires re-inventing the wheels whenever there is a new integrations because of different rules, requirements etc.
2. Slow and costly
3. Vulnerable when integrating with other organisations.