Microsoft KB Archive/247822

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How to use demo SDLC Link Service for 3270 client testing

Article ID: 247822

Article Last Modified on 12/4/2007


  • Microsoft SNA Server 3.0 Service Pack 4
  • Microsoft SNA Server 4.0
  • Microsoft Host Integration Server 2000 Standard Edition
  • Microsoft Host Integration Server 2004 Standard Edition

This article was previously published under Q247822


You can test IBM 3270 terminal emulation connections with the Demo SDLC Link Service included with Microsoft SNA Server.


The Demo SDLC Link Service emulates a live connection to a mainframe computer. The Demo SDLC Link Service is used to demonstrate the capabilities of SNA Server without a live connection to the host. The Demo SDLC Link Service receives messages from the SNA Server computer, and then responds to the messages itself. By loading script files (which are provided), you can run an emulation of a 3270 host. Connections that use the Demo SDLC Link Service appear to the rest of the SNA Server computer as ordinary SDLC connections.

The following steps are required to install a 3270 demo link service and use it for testing:

  1. In the SNA Server Manager, expand the SNA subdomain until the Link Services are displayed
  2. Right-click the Link Services folder, and then insert a link service. Choose Demo Link Service, and then click Add. A new service named SnaDemo1 is created.
  3. From the Script File list box, select either the 3270 Continuous Demo script or the 3270 Logon Demo script.

The 3270 Continuous Demo script runs a test transaction program that continuously sends full screens of data to the emulator.

The 3270 Logon Demo script emulates the 3270 logon and logoff to a mainframe computer.

  1. Click OK.
  2. Create a new SDLC connection on the SNA Server computer.
  3. Create one display LU under that new connection and make sure the LU number is 2. The 3270 Display Demo scripts only work on LU number 2.
  4. Assign that LU to either a Pool or a Configured User or Group of Users that need to do the testing.

The Demo SDLC Link Service can help troubleshoot WAN connectivity problems, SNA Server client setup issues, 3270 Terminal Emulation issues, and can generally be used a starting point for any connectivity troubleshooting.


For more information, see the "What Is a Demo SDLC Link Service?" topic in Chapter 2 of the SNA Administration Guide.

Additional query words: HIS 2000

Keywords: KB247822