FOKUS Broker

Policy-based Service Access, Orchestration and Composition

FOKUS introduces a flexible service environment allowing dynamic service execution through enforcement of policies, service orchestration/composition and service exposure via standardized APIs. All deployed services can be again exposed via different communication channels (APIs) and enable bi-directional service integration. The following image provides on overview of the architecture:

The FOKUS Broker consists of three main functional modules:

• Policy Engine for the expression of service access and execution constraints, which is compliant to the Open Mobile Alliance (OMA) Policy Evaluation, Enforcement, and Management (PEEM).
• Distributed Process Execution engine for service composition and exposure.
• Service Registry for service related information and service discovery.
• SIP & HTTP Servlet Container.
• OMA NGSI, GSMA OneAPI and RCS service and network abstraction.

Together these components allow for policy-based service execution, service discovery, and service composition. Furthermore it provides application layer network abstraction via different protocol APIs as SOAP and REST. The combined functionality enables rapid service prototyping and allows the integration of network-centric services into other service domains.

All software libraries hosted on the FOKUS Broker platform and exposed as services are referred to as “Inside-Out” services as they are provided to 3rd parties. The NGN related services are exposed via REST and SOAP based on OMA Next Generation Service Interfaces (NGSI) specifications.

In order to provide partnerships with external service providers e.g., from the Web 2.0 domain or other enterprises an “outside-In” approach is integrated as well, meaning the integration of non-operator services into an integrated service offering.

Detailed Information:

The Process Execution module is based on an OSGi service environment managing the deployment of services and their execution. Deployed services may be easily exported via different APIs as SOAP, JSON/XML-RPC, REST, RMI or others. The architecture supports the Open Composite Services Architecture (Open CSA) by OASIS. Open CSA enables the idea of a unified way to create software in order to realize the simple and automated integration into service architectures.

Service Composition is provided by an integrated composition engine based on the scripting language standard SCXML (State Chart XML) by W3C. The engine was extended that each state execution can trigger a service invocation to meet the requirements in telecommunications coping with asynchronous, stateful and long-running processes. Using the Service Composition unit, imported services, hosted services and provided services can be combined allowing easy reusability on a very high abstraction level.

The Service Registry provides mechanism for service discovery based on specific searching criteria and storage of information. It also exposed via the NGSI-11 API. The stored information related to platform specific services, respectively 3rd party services contain data about service bindings, dependencies, service description, Service Level Agreement policies and specific service configuration settings.

The Policy Engine implements the OMA PEEM functionality providing request- and service-specific policy. Policies provide a formalism to express besides authorization constraints also Service Level Agreements (SLAs) between an operator and service providers. The concept of policy-based service usage description was extended with dynamic user and service provider specific service capability definition. It is possible not only to define service specific policies but also to correlate those with user specific service settings (e.g., privacy rules).

Service Monitoring provides system-wide and service-specific monitoring functionality. It is possible to be integrated into a domain monitoring OSS via JMX.

The FOKUS Broker framework is based on common standards from the Web, telecommunication, and SOA domain.