Olga,
There is a whole document now on Afaria architecture on http://help.sap.com. The document link is
http://help.sap.com/Download/Multimedia/pdf-afaria7sp8/Afaria_overview.pdf
Frontline is no longer being updated with new releases or documentation. All our current documentation is here:
SAP Afaria 7 SP8 On Premise – SAP Help Portal Page
Tracy