IIS Kapitel 5

• Increase efficiency/ effectivity of business processes
• Realize new business processes
• Support enterprises in mergers and acquisitions
• Supporting reorganization
• Use investment in existing application systems 

• Typologie
  • Point-to-point
  • Bus
  • Hub and Spoke
• Layers
  • Data
  • Business Logic
  • Presentation

• Integration if necessary
• Single Interfaces or adapters necessary 

• Very easy and fast to implement

• Sufficient for small integration Scenarios 

• Tight, static coupling

• Worst case: n*(n-1)/2 interfaces --> rapid increase with higher number of integrated application systems 

• Can be extended infinitely (In theory)
• Connection of an application via interface or adapter 

• Only one interface or adapter per application system

• Scales lineary

• No “single point of failure” 

• Possible redundancy in infrastructure

• Overhead for coordination 

Application systems connected by central hub

• Only few interfaces

• Extensions very easy 

• Very high cost (initial setup/ developmentàvery high risk)

• Single Point of Failure + potential bottleneck 

• Direct acces to databases of existing application systems

• Existing presentation and business logics of application system ignored 

• Relatively easy to implement

• Doable if source code of application systems not available for use 

• Semantic problems

• Security problems

• Not using existing business logic (“double the work”)

• Data model updates require adaption of integration platform 

• Provides relevant information
• Most mature and flexible type of integration

• Semantically strongest approach

• Existing business logic of applications systems used

• Data integrity can be guaranteed 

• Most likely, interfaces or even adapters have to be implemented

• Implementation can be complex

• Source code not available --> very mature interfaces needed

• High project risk 

• Mostly: Screen/Web Scraping

• Program or web-site accessed as if a user is doing it

• Screen content is processed and used for integrated presentation

• Queries to the integrated presentation are translated into a simulated dialogue with application system

• Mostly used for integrated web applications

• Fallback solution if all other approaches fail 

• Relatively easy to implement with tool support

• Works in cases where no interfaces/ documentation/ souce code exist --> because user is simulated 

• No real data/ functionality integration

• High overhead, bad performance, often high latency

• Low flexibility 

• Scalability
• Reliability
• Flexibility
• Maintainability
• Reusability
• Security 

• Software development model based on a contract between a consumer (client) and a provider (server)

  • Breaks business into smaller, distinct units of services or tasks, collectively supporting a functional module or process

  • Allows message interaction between any service consumer and service provider

  • Mostly concept not technology

  • Software provides services

  • Complex services can be built on combination of simple services 

• Software service across heterogeneous platforms
• Location independence
• Loose coupling
• Reduces hardware acquisition costs
• Provides a data bridge between incompatible technologies 

• Increases the ability to meet customer demands more quickly

• Lower costs associated with the maintenance of technology

• Leverages existing investments in technology 

• SOA implementations are costly and time-consuming

• Requires complex security firewalls

• Performance can be inconsistent