inter access point protocol (802.11f) (IAPP)

The Inter Access Point Protocol (IAPP) is a standardized communication protocol with which two neighboring access points( AP) of a WLAN exchange information with each other. IAPP supports the roaming of mobile computers when they want to switch from one radio cell to a neighboring, overlapping radio cell.

Using the IAPP protocol, the mobile computer is already registered with the new access point while it is in the radio range of both access points. The old access point removes it from its radio cell and informs the new radio cell to which the mobile computer has switched without interruption. The new radio cell then registers the new mobile subscriber. If both radio cells, the old and the new, belong to the same subnet, the handover takes place at the datalinklayer; if they belong to different subnets, roaming takes place at the network layer using Mobile- IP( MIP).

The IAPP protocol, described in 802.11f, extends the two standards IEEE 802.11a and 802.11g by roaming mobile clients across multiple WLAN cells. It improves the interoperability of access points from different manufacturers and makes proprietary solutions obsolete.