Using SNA Server with SDLC Multidrop Leased Lines

• Microsoft SNA Server for Windows NT, versions 2.0, 2.1 2.11, 2.11 SP1, and 3.0

SUMMARY

When you use SNA Server on an SDLC multidrop leased line, you should use the following configuration:

• Disable the Constant RTS checkbox in the SNA Server SDLC link service. This is configured in SNA Server Setup for SNA Server versions 2.0, 2.1, 2.11, and 2.11 SP1 and in SNA Server Manager for version 3.0.

     NOTE: In SNA Server 2.0, this option appears as Constant    Carrier.
  
  

• Duplex: Select Half in the SNA Server SDLC connection Advanced Setup dialog box. This is configured in SNA Server Admin for SNA Server versions 2.0, 2.1, 2.11, and 2.11 SP1 and in SNA Server Manager for SNA Server version 3.0.

MORE INFORMATION

If either Constant RTS or Full Duplex is selected, SNA Server always raises the Request to Send (RTS) flag high and creates a point-to-point connection. As a result, other stations on the multidrop line are not able to send data on the line and operations through a multiplexor may fail.

If Half Duplex is selected, SNA Server only raises RTS when it has data to send to the remote system.

This setting should not be confused with half-duplex or full-duplex data transfer. In SNA Server, this setting simply controls SNA Server's use of the RTS signal and should be set to full-duplex to improve performance on an SDLC point-to-point line.

NOTE: The remote system can still be configured to use full-duplex, even though SNA Server is configured as half-duplex.