formsAuthentication and session

hi everyone,
i cannot understand some about security namespace. i read msdn web.security but cannot find my questions answer.
i have a method
void login(string password, string name){
//control password and name
//do some and
Forms.Authentication.SetAuthCookie("abcd", true);
}
Forms.Authentication creats a cookie is it true? when this method (Forms.Authentication) executed Request.IsAuthenticated property returns true.
is Forms.Authentication method creates session? for example Session["acb"]="something";

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