A Channel Processor (CP) is a pair of devices on the database attached to a mainframe channel and used by TDP to communicate with the database. Many CPs can be used for communication between the database and a TDP. The implementation of a CP can vary on different database systems, but the behavior of all CPs is the same. For example, on a DBC/1012, an IFP implements a CP, while on a System 3600, an MCCA on an AP implements a CP. Because the original implementation of an IFP embodied the functions of a CP, the pair of devices were referred to as an IFP.
The devices composing a CP are known to the operating system.
From TDP's perspective, there are two types of CPs, characterized by their communication protocol with TDP: the original Channel Interface Controller (CIC) and the newer Channel Communication Unit (CCU).
CPs and Network Processors may both be used simultaneously by the same TDP.