WIIMLT - shared application instances

[Fabian Kunzke]

Why is it modeled like that? This question often comes up in CSDM workshops. This series of small articles will dive into some specific modeling practices related to not just CSDM but also Service Mapping.

With shared application instances a clear strategy is needed to prevent inconsistencies. Often these shared services are modeled incorrectly and lead to the whole CSDM model loosing accuracy. So let's dive into the deciding factors for modeling it the "right" way.

The starting point

The initial model is very often straight forward:

For this article, we are going to ignore BAs & TS & TSOs to keep the complexity low. They both can be a deciding factor for the remodel. To get some inspiration there, i highly recommend looking at this article from the series.

However, this model is only correct, when the functionality used by both portals is indeed the same. And in many instances this is not the case. And to better/more clearly manage impact inheritance functionality & automated reporting, we need to be more precise, whenever functionality is partially impacted. So a better model may be the following:

Why is this important? Good question. As always with CSDM we need to have a use-case for remodeling. So here is just a list of some:

- Release Management (different release cycles for different functionality)

- Automated outage notifications (when the customer management is down, the interns can still work fine)

- Data Security (customer data might need to meet higher standards)

- Different prioritization (parts of "The App" may need to be supported with different SLAs depending on whether they are linked to Interns or customers)

- Different infrastructure (not depicted)

- Different ownership towards the BA level (not depicted)

and more!

The key priniciple

Not all shared platforms/applications are the same. Some platforms have all their functionality shared across consuming application instances. However, some may not. The list of criteria above will guide you as to when splitting an application instance into multiple is required. And as with the articles before: CSDM must follow your use case. So if you don't have a use case for it (contrary to how it is presented in this article) you don't need to split the model just for the sake of accuracy.

If you have any CSDM related example where you want insights on "why is it modeled like that?", feel free to drop a reply and I will look to add it to this series.