The two-tier, gateway-less environment does not use a DirectConnect for z/OS Option gateway for communication between LAN applications and the mainframe.
Functionality associated with a DirectConnect for z/OS
Option gateway is not present in a gateway-less configuration. However,
one exception is transaction name mapping, which is available for
the Server Option in a
two-tier configuration. For a comparison of functionality between
the environments, see “Gateway and gateway-less environments”.
Figure 2-2 illustrates the use of the Mainframe Connect components in a two-tier, gateway-less environment.
Figure 2-2: Gateway-less environment (without DirectConnect for z/OS Option)
In Figure 2-2, the Sybase or user-written client on the LAN (Windows or UNIX) sends a request for data from the mainframe to either DB2 UDB Option for CICS or Server Option applications on the mainframe. The DB2 UDB Option for CICS accesses DB2 UDB for z/OS and the Server Option application accesses other mainframe data and both return the data or a message to the LAN client.
The LAN client can be:
User-written – user-written clients can be any application using ODBC or JDBC and created with or without Sybase tools, such as PowerBuilder®, Open Client, or Open Server.
Sybase servers acting as clients – these include EAServer, ASE/CIS, and Replication Server when used with the DB2 UDB Option.
The Server Option, the Client Option, and the DB2 UDB Option for CICS all reside on the mainframe.
The database accessed can be a relational source, such as DB2 UDB. Access to non-relational data (not shown in Figure 2-2), such as IMS or VSAM, requires some user application development.
