This section addresses the definition of architectures, specifying the main ICT components that enable the implementation of interaction between institutions putting into practice international social security agreements.

The implementation of agreements involves three architectures:

• International architecture, which addresses interaction at the international level between liaison agencies of different countries;
• National architecture, which addresses interaction at the national level between the liaison agency and competent institutions in the same country;
• Institutional architecture, which addresses the interaction of institutions’ internal ICT systems with the other entities at the international and national levels.

The architectures to apply on specific agreements depend on the characteristics of the agreement.

While the international architecture of multilateral agreements requires common services and a “trusted third organization”, bilateral agreements could be based on point-to-point connections between the liaison agencies (e.g. using Web Services protocols).

In turn, the national architecture applies only when there are several national institutions coordinating with each other; it is not necessary when there is only one institution involved in the agreement, which is a very frequent scenario. Table C.2.1 summarizes the criteria.

Table C.2.1. Criteria for architectures of international agreements