Real-world deployments are likely to be mixtures of these basic approaches. For example, it will be quite common for an RP to route traffic to a AAA proxy within an organization. That proxy could then use any of the above three methods to get closer to the IdP. It is also likely that, rather than being directly reachable, the IdP may have a proxy on the edge of its organization. Federations will likely provide a traditional AAA proxy interface even if they also provide another mechanism for increased efficiency or security.