The choice of a network driver depends on several factors:
Network type—SNA or TCP/IP
Network environment—two-tier (TCP/IP only) or three-tier (SNA only)
Operating environment—CICS or MVS
This section explains why you might want to choose a particular driver in each environment.
Because non-MVS platforms do not support LU 6.2 in their operating systems, if your network type is SNA, then you must use a three-tier network environment with a gateway. In a three-tier (gateway-enabled) environment, you must use either an LU 6.2 or CPI-C driver.
If your network type is TCP/IP, your network environment must be two-tier (gateway-less). The choice between IBM TCP/IP and Interlink depends on which product is installed in the network environment, although Open ClientConnect supports both concurrently.
This section explains the drivers used in CICS and MVS environments.
The following drivers are supported in the CICS environment:
LU 6.2
CPI-C
IBM TCP/IP
Interlink TCP/IP
The LU 6.2 driver supports only incoming transactions sent to the CICS message queue. It does not support Open Client outbound requests from the mainframe. With the LU 6.2 driver, CICS builds an entire result set in the message queue and sends that entire result set to the MSG.
The CPI-C driver supports both Open Client and Open Server requests. It does not use the CICS message queue to send or receive requests. Therefore, result sets sent by Open Server using the CPI-C driver can be interrupted. However, with the LU 6.2 driver, if a client does a CTRL-C to cancel the result set, the gateway must read the entire result set and throw it away.
The following drivers are supported in the MVS environment:
CPI-C
IBM TCP/IP
Interlink TCP/IP
