SAML — how to process a request?

I'm a newbie at SAML. My question is simple:

Upon开发者_开发技巧 a SAML request, what do IdPs usually do?

I guess they first parse the XML — and then? Can anybody describe the steps? I mean the common steps, that every IdP has to do at the very least.

The wikipedia article on this actually contains a lot of the information you need:

http://en.wikipedia.org/wiki/SAML_2.0

Look at the example SAML 2.0 Auth Request and Response plus the list of steps involved. The simplest method is the "SP POST Request IdP POST Response" so start with that. It's not the only option for deploying SAML 2.0, there's others also described there as well. Hope that helps.