The ECP knows or is capable of discovering which identity provider the service provider trusts.
The Enhanced Client or Proxy (ECP) profile of the SAML 2.0 specification is useful in the following situations:
You have a client with extended capabilities and you want the client to take on more responsibility in the exchange. For example, the client can determine the appropriate identity provider.
Your client has limited capabilities so you delegate some of these tasks to an enhanced proxy. For example, a wireless access point (WAP).
You cannot use other bindings. Some possible examples are as follows:
The client does not support redirects.
A firewall prevents the identity provider and service provider from communicating directly, preventing the artifact binding.
The ECP profile enables the client to contact the identity provider with the authentication request generated by the service provider. Exchanges between the ECP and the service provider use PAOS.
For more information, see the documentation supplied by the identity provider vendor.