What Is SNA Server?

Microsoft SNA Server is a suite of integrated services that provides access to mainframe data and application resources from a client workstation. SNA Server provides the necessary mainframe connectivity and integrates the desktop environment with an IBM mainframe system to support line-of-business applications that require services such as online transaction processing and Web access.

SNA Server acts as an SNA gateway for the enterprise and integrates the Windows NT Server systems on a LAN or WAN with IBM mainframe and AS/400 mainframe systems using two types of connections:

Server-to-Mainframe Provides the physical connections (Physical Units) and logical connections (Logical Units) between the SNA Server and the mainframe system.
Client-to-Server Provides the client/server network connections to the non-SNA systems on the LAN or WAN, such as workstations or server applications, that require access to SNA applications.

There is no SNA Server footprint on the mainframe. SNA Server uses standard communication protocols (such as LU 6.2) for communicating between the Windows NT Server computer and the mainframe computer.

SNA Server contains three components that support integrated mainframe data and transaction access, as described in the following table.

Component	Description	Discussed in this section
OLEDB/DDM Provider	Reads and writes records in VSAM and AS/400 files.	Accessing VSAM and AS/400 Files
Host Data Replicator (HDR)	Copies relational data between mainframe systems and SQL Server databases.	Accessing a Mainframe Database Using the Host Data Replicator
Component Object Model Transaction Integrator (COMTI)	Extends transactions from the Windows NT environment to the mainframe CICS and IMS environment (previously known as "Cedar").	Integrating with Mainframe Transactions

All three SNA Server components can be used with any development language that adheres to the Component Object Model (COM), including the following Microsoft Visual Studio languages:

Microsoft^® Visual Basic^®
Microsoft^® Visual C++^®
Microsoft^® Visual J++™

For More Information For more information about SNA Server, see the Web site at http://www.microsoft.com/sna. For additional information on how SNA Server makes the connection to the mainframe environment, search online for "Microsoft SNA Server Planning Guide," "Microsoft SNA Server Administration Guide," and "An Overview of Microsoft "Cedar"" in MSDN Library Visual Studio 6.0.