# Guide to OpenIG
2.2. How It Works In Detail

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### 2.2.10. Federation Service (Federation Gateway)

When the Federation Service is enabled, OpenIG acts as the Service Provider in a Circle of Trust with a SAML2 compliant Identity Provider. The Federation service supports both IDP and SP initiated SAML2 profiles. The Federation Gateway may be a Service Provider in the classic Federation use case where the IDP and SP are different companies or domains. The OpenIG SP can also be a standards based alternative to an OpenAM policy agent for internal enterprise applications that want to move away from installing agents with web and web application servers.