PMDF consists of a large number of components, but the central unifying construct in PMDF is the channel. A channel represents a connection with another computer system or group of systems. The actual hardware connection or software transport or both may vary widely from one channel to the next. Only the system manager need know anything about PMDF's channels; users are never aware of the existence of channels and only see a single, uniform interface regardless of how messages reach their destination.

The channel/host table is stored in the PMDF configuration file; see Section 2.1 for an overview of the PMDF configuration file format.