The Call Home is either realized by sending an email to IBM or through an “Electronic Service Agent”. The Service Agent can establish an SSL or IPSec secured connection to dedicated IBM servers and report issues by opening a support ticket in the IBM Support Ticketing System. Following a call home, IBM triggers necessary actions to solve the issue. These actions can include ordering replacement parts and, if needed, dispatching a technician for on-site support.
Some IBM System Storage products come with a pre-installed AOS client to allow remote access via AOS. For products that do not have an AOS client installed, AOS configured with port-forwarding can still be used as a remote access gateway to enable IBM support access.
You can read more about AOS in the IBM Redbooks publication: Introduction to Assist on-Site for Storage, REDP-4889