Multiple simultaneous requests from the same client.

[abpprkonsalting]

The central server must be ready to receive several redirections from the client, to which it must respond with the initial page in which the client select the type of authentication he want to use. These redirects will have the same variables (redirect, userMAC, deviceMAC and token), and to all of them the server will respond with the same page. Once the client clicks the "Authenticate with FaceBook" button, and that information reaches the website, the later should discard any subsequent post that arrives from the client answering with an error page in which the client is informed that the authentication process is already happening on another page. This is to prevent the client from having two browsers opened by mistake or ignorance, and is taking the process in the two browsers at the same time.