Use rights published in July 2011 clarify how customers can move licenses bought in volume licensing to cloud hosting providers. This "license mobility through Software Assurance" licensing option, a benefit of Microsoft's Software Assurance (SA) program, provides one way for customers to move Microsoft server-based applications into off-premises data centers hosted by Microsoft service provider hosters, who in turn can reduce infrastructure and management costs. The new use rights reveal important differences between licensing products on-premises and licensing them off-premises with license mobility through SA. Customers and service provider hosters will need to study these differences, because the new use rights could mean that an on-premises software architecture would require additional licenses when moved to the cloud.

Moving Licenses to Cloud Service Provider Hosters

The new use rights were published in the July 2011 Product Use Rights (PUR) document, which repeats and supplements the software license terms of products with additional rights and restrictions affecting volume licensing customers. The use rights concern movement of licenses bought in Microsoft volume licensing programs from on-premises servers to servers at service provider hosters. Longstanding Microsoft policy allows volume licensing customers to move licenses for server applications from on-premises servers to servers located at a third-party service provider hoster, as long as the servers at the hoster are dedicated to (i.e., used exclusively by) the customer owning the license. In July 2011, Microsoft added license mobility through SA, which allows customers with active SA to move many types of server licenses to a service provider hoster's multitenant servers, which are shared with other hosting customers.

Movement of on-premises licenses to a service provider hoster's dedicated or multitenant servers are valuable options for customers who want to outsource management of Microsoft-based systems. When customers move existing licenses to servers at a service provider hoster (the cloud), this frees the service provider hoster from having to pay Microsoft Service Provider License Agreement (SPLA) rental fees for those licenses.

Differences Between On-Premises and the Cloud

Licenses moved to service provider hosters under license mobility through SA do not always grant the same rights that those licenses do on-premises. Some of the differences benefit customers and service provider hosters by simplifying compliance, but others limit the types of workloads that can be handled by the licensed systems off-premises. (See the chart "How On-Premises and Cloud Virtualization Use Rights Differ".)

The most important differences concern the use rights for licensing multiple operating system environments (OSEs) on a server. An OSE refers to an OS instance running on either a physical or virtual server. In the vast majority of cases, a server will have multiple OSEs because it is hosting multiple virtual machines (VMs), each with its own OSE. Consequently, the license mobility through SA use rights for OSEs affects how service provider hosters may use VMs and virtualization to run software for customers.

The three major ways use rights can differ under license mobility through SA are as follows:

Fewer OSEs may be covered by a single license. If a license covers use of a product within multiple OSEs when applied to an on-premises server, in most cases it will cover only one OSE when applied to a multitenant server at a service provider hoster. For example, SQL Server Enterprise edition per-server and per-processor licenses with active SA subscriptions attached cover an unlimited number of OSEs on a licensed on-premises server (in most circumstances, under current rules). This difference can be significant for certain scenarios because, depending on architecture, the license(s) a customer uses to cover a set of on-premises workloads might be insufficient to cover the same workloads when reassigned to a service provider hoster.

Note that the right for SA customers to run SQL Server Enterprise in an unlimited number of OSEs on the licensed server will end when the next version of SQL Server ships; thereafter each license will cover four OSEs.

If a single license covers more than one OSE when reassigned to a service provider hoster, the OSEs are not required to run on the same physical server. In the case of System Center Management Suite Enterprise and System Center Management Suite Datacenter, four OSEs are covered by a single license, but the OSEs don't have to run on the same physical server as is the case with on-premises licensing. This could work in the service provider hoster's and customer's favor by easing one aspect of license compliance.

Processor resources an OSE can access under a single license may increase. A Standard edition processor license for SQL Server, BizTalk Server, or Forefront Threat Management Gateway covers only one OSE in both on-premises and cloud scenarios. However, when the license is applied to an on-premises server, the OSE requires more than one processor license if it is configured to use more than one "virtual processor." (Microsoft defines a virtual processor for licensing purposes as one physical processor's worth of computational power, which is a very different definition than the industry-accepted technical definition of virtual processor.) For example, an OSE configured to use three cores' worth of computational power on a server with two dual-core processors has access to 1.5 virtual processors, and Microsoft requires customers to round up and have two processor licenses. When assigned to the cloud, the same processor license allows an OSE to utilize up to four virtual processors. Assuming a service provider hoster uses servers with four or fewer physical processors, it wouldn't be technically possible for an OSE to utilize more than four virtual processors and thus any OSE running the Standard edition of these server applications would always be covered by moving one processor license from on-premises to the cloud.

Customer Still Responsible for License Compliance

According to Microsoft's PUR document, customers who use license mobility through SA "will be responsible for third parties' actions with regard to software deployed and managed on your behalf." So contracting with a qualified "License Mobility through SA Partner" and submitting a "License Mobility Validation form" detailing the licenses being reassigned does not absolve customers of compliance responsibilities or risks. For starters, a customer's existing on-premises asset management tools and processes will likely require augmentation or modification to track license compliance by a service provider. Furthermore, in the event Microsoft audits a service provider hoster, the audit could possibly also involve any customer who moved licenses to the service provider hoster.


Options and rules for reassigning server licenses with SA to the cloud are detailed in "Changes Reduce License Costs for Hosting" on page 20 of the June 2011 Update.

Microsoft's quarterly PUR document is available via a link at The July 2011 edition of the PUR details the expansion of license mobility rights for SA customers in "Appendix 1 — Software Assurance Benefits."

Microsoft's monthly Product List document, which details the license mobility through SA benefit (see the section "License Mobility through Software Assurance"), is available via a link at

The SPLA home page is at