The client program for your CICS application need not use BMS. You can have a graphical/ Web user interface that is written in Java or runs under Microsoft .NET or uses Dialog System. In this case you use the IBM External Call Interface (ECI) to communicate with the CICS application.
You use ECI calls in your client program to communicate with the CICS application running under Enterprise Server. The ECI calls from your client program are passed through the IBM CICS Transaction Gateway to Enterprise Server.
Enterprise Server supports standard ECI calls to Mainframe Sub-System regions. ECI allows non-CICS programs running outside the server to invoke COMMAREA-based CICS programs within a region, opening up access to legacy business logic.
ECI client programs can be running on the same machine as the enterprise server or on different physical hardware. In either case the requests are submitted to the target region through the communication layer via the “Web Services and J2EE” listener.
The ECI entry points such as CICSEXTERNALCALL are exposed by the casbnccl module which is supplied as a dynamic load library on Windows and a callable shared object on UNIX and Linux platforms.
Client programs should call this module either by coding a CALL statement or by using an INITCALL(casbnccl) compilation directive.
ECI support is enabled by default in an MSS type region - no further configuration of the server is required.
The region to which the request is directed is identified through the ECI-SERVER variable in the ECI parameter block and takes a null or space padded value which must match a server defined in the target MFDS repository. The location of this can be specified either by editing the mf-client.dat file found in %ProgramFiles(x86)%\Micro Focus\Studio Enterprise Edition x.x\base\bin by default, or by setting the environment variable ES_ECI_CCITCP2 to the value <host>:<mfds-port>, for example ES_ECI_CCITCP2=localhost:86. You can also override and bypass the lookup by setting the environment variable ES_ECI_SOCKET to the value <host>:<Web-Services-listener-port>.