CTG 란?

아직 정리 안되어 있음 ^^;

What is CTG and how does it compare to HostBridge?

CICS Transaction Gateway (CTG) is an IBM software product that runs on a middle-tier platform (usually). It supports two primary interfaces to CICS transactions: ECI and EPI.

EPI is a terminal emulation interface, like HLLAPI. It allows a program on the server to interact with a CICS terminal-oriented transaction using terminal emulation and "screen scraping" techniques.
ECI is an interface that allows a program on the server to interact with a CICS COMMAREA transaction.
HostBridge does not require CTG. However, if a customer wants to use CTG as their gateway into the mainframe then the ECI interface can communicate between a program on the middle-tier server and HostBridge. (HostBridge supports a COMMAREA interface.) The only scenario in which CTG would be required would be if a customer wants to use SNA as the communication protocol to the mainframe. This is actually why CTG came into being, but it is a very rare situation these days.

Under no circumstances do we use the EPI interface (HostBridge is all about eradicating screen scraping, not using it!)

The bottom line is that HostBridge and CTG are not competitive, and can be complementary. Thus, you can't really say that one is superior to another. HostBridge XML-enables CICS BMS transactions. CTG does not. The only case in which CTG is required with HostBridge is if the customer wants to use SNA between the middle tier and the mainframe. In all other cases CTG is unnecessary when using HostBridge