Open APIs

Hi all,

I would like to start a discussion about how to model and manage shared CFS access across multiple services in a TM Forum–aligned architecture.

In TMFS003, Global Catalog view, the model represents a single connectivity service where:

• a Fiber access underpins the top service 

• service Connectivity depend on it

• the model is shown for a single product/service instance

However, what is not covered in the example is a very common real-world scenario: multiple independent services (e.g., VPN, Voice) sharing the same physical access.

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Problem statement

Assume the following situation:

• A customer has already ordered a connectivity service (e.g., Internet over Fiber), which resulted in:

  • one Fiber Access instance

  • one or more dependent services

• Later, the same customer orders an additional service (e.g., VPN) on the same location, which should:

  • reuse the existing physical access

  • not create a new one

This raises several modeling questions across layers.

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Questions

1. Product Catalog (TMF620)

In the Fiber Contract Silver example, access is implicitly part of the product decomposition.

• How would you model multiple products that may share the same access?

• Do you:

  • keep products completely independent (no explicit shared component)?

  • or introduce some form of "access product" or shared component in the catalog?

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2. Product Order (TMF622)

When a second service is ordered:

• How does the order express reuse of an existing access?

• Is the reference to an existing instance:

  • explicitly passed in the order?

  • or resolved entirely by orchestration logic?

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3. Product Inventory (TMF637)

• How do you represent that:

  • multiple services (Internet, VPN, etc.)

  • are linked to a single shared Access instance?

• Do you rely purely on:

  • reliesOn relationships between ptoducts?

• How do you manage lifecycle:

  • when one service is terminated but others still depend on the same access?

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4. Orchestration & lifecycle

• What is the recommended pattern to:

  • avoid duplicate access creation

  • handle reference counting / dependency tracking

  • ensure proper cleanup (delete access only when last dependent service is removed)?

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Jan Brnka
T-Mobile Czech & Slovak Telekom, a.s.
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