How to connect sign in with backend (web api) services

[mwpowellhtx]

I'm assuming it must involve some degree of cookies passing between client and server?

That is, in my Startup.ConfigureAuth(IAppBuilder app), I've got this:

            // Enable the application to use a cookie to store information for the signed in user
            app.UseCookieAuthentication(new CookieAuthenticationOptions
            {
                AuthenticationType = DefaultAuthenticationTypes.ApplicationCookie,
                LoginPath = new PathString("/login")
            });

            // Use a cookie to temporarily store information about a user logging in with a third party login provider
            app.UseExternalSignInCookie(DefaultAuthenticationTypes.ExternalCookie);

But am not entirely sure what that means. I don't want to redirect to /login, for instance, if I can just pass the front page sign in details, user name and/or email and password, with or without cookie, to a backend authentication service.

Then from that point forward, how to maintain some level of authentication. i.e. user id with or without session id for security reasons. That sort of thing.