In SharePoint 2013, the following applications can be shared across SharePoint 2013 server farms.
- Business Data Connectivity
- Machine Translation
- Managed Metadata
- User Profile
- Secure Store
A SharePoint 2010 farm can consume services from a SharePoint 2013 Server farm. This allows for upgrade of multi-farm environments in which a farm hosting service applications is upgraded first. In this scenario, the service applications and features that the SharePoint 2010 farm experiences are limited to those that are available in SharePoint 2010. For example, a SharePoint 2010 farm cannot consume the Machine Translation service application from a SharePoint Server 2013 farm and does not benefit from the new features of the User Profile service application.
Additionally, If the server farms are located in different domains, the User Profile service application requires both domains to trust one another. For the Business Data Connectivity service and Secure Store service application administration features to work from the consuming farm, the domain of the publishing farm must trust the domain of the consuming farm. Other cross-farm service applications work without a trust requirement between domains.