Windows Server Update Services (WSUS) enables information technology administrators to deploy the latest Microsoft product updates. You can use WSUS to fully manage the distribution of updates that are released through Microsoft Update to computers on your network.
A WSUS server provides features that you can use to manage and distribute updates through a management console. A WSUS server can also be the update source for other WSUS servers, also known as an upstream server. In a WSUS implementation, at least one WSUS server on your network must be able to connect to Microsoft Update to get available update information.