APPN manages communication between machines, including routing, and operates at the transport and network layers.
By contrast, APPC manages communication between programs, operating at the application and presentation layers.
The designation peer-to-peer in the case of APPN refers to its independence from a central point of control, similar to the way that a FireWire PC connection allows a video camera to talk directly to a disk drive on the FireWire network.
[5] APPN is supported on a variety of IBM and non-IBM "intelligent" devices and software.
It is available on mainframes, AS/400, System/36, OS/2 via Communications Server,[6] Cisco equipment,[7] and Microsoft Host Integration Services (HIS) for Windows.