title: .NET/WCF: Are WCF services on a different "tier" than ASP.NET?
body: <p>At work, we have the UI layer (CSS, HTML, JavaScript&mdash;all executes in the browser), middle-tier (ASP.NET MVC and our C# library&mdash;all executes server-side) layer, a service layer (WCF services that the middle-tier calls as-needed), and a DBO layer that WCF services use instances of.</p>
  
  <p>When the middle-tier (e.g. a static .cs class) calls a WCF service, it uses an instance of that service. </p>
  
  <p>My question is, when I use a class method in our middle-tier that uses a instance WCF service, does that method cause a cross-tiers connection?</p>
  
  <p>Does a "connection" have to be established between the WCF service and the class? We're referencing all our services via Project references to the services' .DLL files.</p>