Single Window Systems
In the OIC Member States
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5. Regional Single Window IT Architecture
The IT architecture model is a critical aspect of a RSW. Two IT architecture models are applicable:
 Peer-to-peer model or distributed (decentralised) IT Architecture;
 Centralised IT Architecture.
The peer-to-peer model or distributed IT Architecture requires a common exchange layer to
dispatch messages and to co-ordinate the distribution of messages (data and documents)
between two participating IT systems without any centralisedmiddleware platform. Without any
routing services this model relies on direct communication between the various services /
applications. This is compromising on the re-usability of communications and networking
services. The interoperability logic is separated out into an isolated IT infrastructure and serves
the needs of bi-directional communication between the national SWs and their respective
stakeholders.
The centralised RSW IT architecture model implies the establishment of a common centralised
service - middleware software architecture (example enterprise service bus - ESB). This provides
a communication system between service consumers and service providers on the
interoperability and the interconnectivity level, such as message transformation, protocol
conversion and routing services. This model supports the heterogeneity of national IT
architectures, and incorporates requirements for service-oriented architecture and
interoperability.
The RSW centralised IT architecture must offer a range of services to fulfil the RSW integration
requirements with the other national SW (internal and external portal services / applications and
interacting stakeholder’s subsystems within the NSW domains. These architecture components
are: service / application server, portal server, database server (for the reference data) and the
ESB and supportive infrastructure components - demilitarized zone (DMZ), security services and
users directory. Another important element of the RSW centralised IT architecture is the
reference data repository that must be used by the RSW participating countries.
Examples from the World
One of the operational peer-to-peer IT Architecture model for exchange of customs data is EU SEED
project79 , that exchanges data between six Western Balkan Customs Administrations on a pre-
arrival basis. The EU SEED IT architecture is fully based on the peer-to-peer model with common
middleware platform that is replicated in participating countries. The EU SEED system has an
integrated computerised data matching that contributes to the minimization of human
interventions.
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