CAPs are site system roles that provide the main communication point between client and server computers in the SMS hierarchy.
When a client is assigned to one or more sites, it receives a list of CAPs for each of those sites. A client sends inventory data and status messages to a CAP, and it receives advertisements from a CAP. When a program starts on a client, the Advertised Programs Client Agent checks the CAP to find the available distribution points for the particular program.
Note SMS does not support CAPs on FAT partitions. The site system that you want to configure as a CAP must have at least one NTFS partition available.
Designate a CAP
Distributing Software to Clients
Distributing Software to Clients Overview