Auto deployment rules are a new feature of SCCM 2012. Among other things, this feature was developed to optimize the deployment of definition updates while minimizing the impact on your network connections.
Previous versions of SCEP relied on either Microsoft Updates in the cloud, WSUS, or UNC file shares (all of which can still be used in SCEP) to push out definitions. The use of ADRs allows you to tap into your existing SCCM distribution points without the need for human interaction to keep them up-to-date.
The creation and management of automatic deployment rules is done within the Software Updates Management (SUM) component of SCCM 2012. Therefore, it is required that the SCCM server on which you are configuring these rules has the software update point installed.
In a large-scale hierarchical SCCM environment, this task would typically be conducted on the CAS.