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ViaSQL Has Two Ways to Connect to z/OS and VSE/ESA

Fast and easy ODBC or JDBC access to data and applications on z/OS and VSE. Connect the desktop, the web server, or the browser directly to the mainframe, using either the ViaSQL Direct ODBC Driver or the ViaSQL Direct JDBC Driver.
All the capabilities of ViaSQL Direct, plus extended functionality for behind-the-scenes data management. The ViaSQL Gateway, an NT, 2002, or 2003-based server process, provides the connectivity to the mainframe.

From the application's perspective, it doesn't really matter whether it connects to the mainframe directly, or through a gateway. In either case, the results and messages returned to the requesting application are the same. There are, however, some practical considerations that might favor one method over another:
On the one hand, a gateway-less implementation is simpler in terms of installation and configuration, and does not require the use of a separate LAN-based server machine. This method requires that communication software reside on each machine where the ViaSQL Direct ODBC Driver or ViaSQL Direct JDBC Driver is installed. For TCP/IP connections this is usually a trivial requirement, but for ODBC LU6.2 connections, Microsoft's SNA Server must be installed and licensed on each client machine.
On the other hand, in an implementation that uses a gateway, some of the software and much of the processing can be offloaded from the client machine, and configuration and administration are centralized. In addition, various kinds of advanced functionality becomes possible, like TRANSFERs and Client Services Applications.

ViaSQL lets you deploy the components that are best suited to your application requirements.