Knowing that to provide SSO to my customers, employees and partners I need to integrate my application into the federation infrastructure; the first question that is asked is "How do I integrate my application?". There are a number of mechanisms that can be used for this "last-mile" integrate, so to plan for application integration a number of components should be considered:

Application Format - The format of the application. Whether it is a web application, a mobile application or an API or web service.

Application Platform - The application platform can help determine the simplest integration method. The platform includes the language and framework the application is written in (i.e. Java / Spring or .NET 4.5) as well as the web application server the application is hosted on (i.e. Apache or IIS).

Application Deployment Model - Whether the application is cloud-hosted or deployed inside the firewall can also help determine the simplest integration method. For example PingOne provides a simple REST interface to enable SSO into a cloud-hosted application whereas PingFederate is a a software component but enables more options for complex integrations.

API Requirements - If the application needs to talk to specific API's it may be simpler to define the authentication mechanism around those services (i.e. if the application requires user authentication and accesses OAuth 2.0 protected REST web services, then OpenID Connect protocol is a good choice).

Availability of Source Code - There may be applications where the source code is not available (i.e. COTS application) or that the source code is not supported. Perhaps a mechanism that doesn't require code changes is the most appropriate.