SessionInitiationCommonQueryParameters

The protocol independent parameters are

Parameter Name	Parameter Value Type	Description

Parameter Name	Parameter Value Type	Description
entityID	URI	The IdP to request authentication from.
target	absolute URL	The URL to return the user to after authenticating. If unspecified, the homeURL attribute for the application is used.
acsIndex	string	The index value of the <md:AssertionConsumerService> element to instruct the IdP to use in returning an assertion to the SP
authnContextClassRef	whitespace-delimited URIs	Requests that particular authentication context classes be used by the IdP.

Service Provider 3