ISO 17624:2009 provides the specifications of:

common AVI/ AEI transaction requirements, which define the common steps of any AVI/ AEI transaction
AVI/ AEI application interface to standardized wireless protocols (referred to as the " Air Interface" ) supporting the AVI transaction requirements, so as to enable interoperability.

ISO 17624:2009 is an interface standard, adhering to the open systems interconnection (OSI) philosophy (ISO/ IEC 7498‑1), and it is as such not concerned with the implementation choices to be realized at either side of the air interface between the " Fixed Equipment" and " OBE" .