The connections that CICS Transaction Gateway uses when forwarding client requests to CICS must be configured for the supported protocol.
EXCI and IPIC are the communications interfaces for CICS® Transaction Gateway for z/OS®. If you are using IPIC exclusively, you do not need to configure EXCI. Use the CTG_EXCI_INIT environment variable to specify that EXCI is not loaded. For more information on this variable, see Environment variables: local and remote mode.