FICON Channel-to-Channel Reference

SB10-7187-00

This publication describes the Fibre Connection (FICON®) Channel-to-Channel adapter. FICON allows a Fibre Channel path to function as both a channel and a Channel-to-Channel (CTC) simultaneously.

A FICON channel-to-channel (CTC) connection consists of an input/output (I/O) device that is used by a program in one system to communicate with a program in another system. A CTC communication is established between two programs when the adapter is selected to respond to channel-command words (CCWs) that are issued by the channels in the CTC connection.

FICON CTC increases the connectivity options for customers. Now, each of any two systems that have at least one FICON channel connected to the network can have CTC connections set up between them with no additional cost. Customers no longer have to dedicate channel path (CHPID) resources to the CTC function. In the Fibre Connection (FICON) channel I/O interface environment, a stand-alone CTC adapter unit is not used to provide the switching function. The switching function is provided by the FICON Director. CTC connections between channels can be made by going through a FICON Director. The CTC adapter function is implemented logically between connecting channels and resides in the FICON channel.

The fibre channel path functions as both a channel and a channel-to-channel at the same time. It provides self configuration and load balancing of the CTC function among FICON channel paths, including proper configuration when the target channel does not have an integrated CTC.

This publication is available for download here.