Appendix A: Gateway-less and gateway-enabled environments

General DirectConnect for z/OS Option functionality

The following DirectConnect for z/OS Option features are available to the three-tier user and unavailable in a two-tier environment:

Logging, tracing, and accounting – your environment can use DirectConnect for z/OS Option facilities for logging, tracing, and accounting.
GUI configuration and multi-user management – any GUI configuration and user-management tools available with the DirectConnect for z/OS Option are available to the three-tier user.
SNA connectivity – the SNA connectivity protocol can only be used through a gateway, which provides TCP/IP-to-SNA protocol conversion. SNA connectivity is supported only in communication from the LAN to the mainframe.
Access to multiple CICS regions – LAN client applications in a three-tier environment may access multiple CICS regions at one time.
Transaction grouping – transactions may be managed as a group in a three-tier environment.
Security – additional levels of security may be implemented by the gateway in a three-tier environment.

DirectConnect for z/OS Option transaction name mapping is provided in the Server Option in a two-tier environment.