Licensing is probably the most dreaded component we have to deal with. (Well, apart from the users. Boy our jobs would be easy if there weren't any users!) In Citrix Presentation Server 4.5 environments, we need to deal with both Microsoft and Citrix licenses, not to mention the licenses for the applications that we're actually delivering for the users. Both Windows Server 2003 Terminal Services and Presentation Server have significant licensing provisions to ensure that licenses are paid for. Gone are the days when you could carelessly install applications and assume that the accounting department paid for them.
The only thing that changes faster than technology is the licensing of technology. For that reason, it's important to remember that this licensing chapter was up-to-date only when it was written. It’s always possible that the details of Microsoft or Citrix licensing have changed since then. You can find the latest details of each at www.microsoft.com/licensing and www.citrix.com/licensing.
Because Microsoft Windows licensing and Presentation Server licensing are so different, we'll address each one separately in this chapter.
Once we cover those two main topics, we'll close the chapter with a discussion about application licensing. This is really interesting, because technologies like virtualization and server-based computing don't fit into the "traditional" mindset that a lot of software vendors have. For example, vendors that charge per-processor each have their own interpretation of what a "processor" is. (Does Hyperthreading count? How about multi-core?) Vendors that license "per server" have to deal with hardware virtualization. (Is a server a physical thing? Or an instance of an OS?) Should vendors instead license their applications based on the instances where they're used? In that case, what about a user who runs an application locally via application streaming on most days, but also uses the application via Presentation Server. How many application licenses is that?
Let's begin now with the licensing for Microsoft Windows Server 2003 Terminal Services.