Internal Coupling channel

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The Internal Coupling channel emulates the coupling facility functions in LIC between images within a single system. Internal Coupling channel implementation is completely logical, requiring no channel or even cable hardware. However, a CHPID number must be defined in the IOCDS. Internal Coupling channels cannot be used for coupling connections to images in external systems.

Partitions with Internal Coupling channels can also have coupling facility channels which allow external system coupling. ICs, which use the system bus, are extremely fast (approximately 6 GB/second).

Internal Coupling channels have channel path type ICP (Internal Coupling Peer). Internal Coupling channels are identified by 2 CHPIDs representing the two ends of a coupling link. The rules that apply to the ICP CHPID type are the same as those which apply to external coupling link types, with the exception that the following functions are not supported:

  • Service On/Off
  • Reset I/O Interface
  • Reset Error Thresholds
  • Swap Channel Path
  • CHPID Reassign
  • Channel Diagnostic Monitor
  • R/V
  • Configuration Manager Vital Product Data (VPD)

Internal coupling channels have improved coupling performance over coupling facility channels.