There was an amount of kerfuffle when VMware released vSphere v5.0 and moved to a memory centric licensing model. We speculated on whether other vendors would follow suit. Microsoft has unveiled Windows 2012 licensing terms, which it claims make licensing simpler and better value . The thing to commit to memory? There are now only four versions, and licensing is processor and client access license based.

Windows 2012 Licensing … Editions

Microsoft has aimed to make things far simpler with Windows 2012. Functionality differences between Datacenter/Standard editions are gone – the Enterprise edition no longer exists.

Edition Ideal for… High Level Feature Comparison Licensing Model Pricing Open NL (US$)
Datacenter
Highly virtualized
private & hybrid
cloud environments 

Full Windows
Server functionality
with unlimited
virtual instances
Processor + CAL* $4,809**
Standard  Low density or non-
virtualized
environments
 Full Windows
Server functionality
with two virtual
instances
Processor + CAL*

 $882**

Essentials Small business
environments
Simpler interface,
pre-configured
connectivity to
cloud based services; no
virtualization rights 
 Server (25 User
Account Limit)
$425** 
Foundation  Economical general
purpose server
 General purpose
server functionality
with no
virtualization rights
 Server (15 User
Account Limit)
 OEM Only

*CALs are required for every user or device accessing a server directly or indirectly. See theProduct Use Rights for details.

 **Pricing represents Open No Level (NL) ERP. For your specific pricing, contact your Microsoft reseller

With Windows 2012 Datacenter Microsoft has consolidated the two licenses into one and left the price at $4,809. Unlimited virtualisation licensing. Thus, if you buy one copy of Datacenter for a dual CPU host (any virtualisation) you get unlimited installations of Windows Server 2012 or lower (any edition) for unlimited VMs on that host.
Windows 2012 Standard Edition has had a cost increase – however while the number of virtual instances you can support remains the same (it’s 2) – Windows 2012 Standard Edition has the same product features as datacentre – and supports up to 640 processors and 4TB memory.

But…but…Enterprise Edition?

If you’ve purchased Microsoft’s Software Assurance then Enterprise Edition becomes two Windows 2012 Standard… remember – Standard Edition has the full  product feature set – including clustering.

Client Access Licenses (CALs)

Nothing to see here.  Just continue to license clients for the highest version of Windows Server that they use. RDS CAL licensing is not changing either.  Anyone running either Web (only) or HPC workloads (only) on their servers do not require CALs.
Neither Window Server 2012 Essentials or Windows Server 2012 Foundation require CALs.

Simpler, Better Value?

Perhaps with the release of 2012, Microsoft have a rare moment of  being a vendor that made a change to product licensing without upsetting someone. Although there’s always time: some organisations might be disgruntled with the increased price of Standard Edition despite the increase in features, and some home users may look forlornly at the demise of Home Server or maybe they’ll be excited at the prospect of change.
Because, it is fair to say that Microsoft have made licensing in your data centre more straightforward. Windows 2012 comes in Standard or Datacenter. They are licensed by processor and CALs. They both come with all the scalability and all the features including Hyper-V. Indeed, there is still a free Hyper-V Server 2012 that can be used for VDI environments, or Linux VMs.
Memory licensing? <shudders>
For more detailed information you can view Microsoft’s release information,  where they have a Licensing and Pricing FAQ. I’d also recommend a visit to Aidan Finn’s analysis of  Windows Server 2012 Licensing In Detail.