SNA Server Sends Sense Code 400D to Host after CD Received

 Last reviewed: November 5, 1997
Article ID: Q160991
The information in this article applies to:
  • Microsoft SNA Server version 2.11, 2.11 Service Pack 1, and 3.0

SUMMARY

When SNA Server receives an SNA message from the host with the Change-Direction (CD) bit set on a full duplex LU0 session, SNA Server will reject the message with sense code 400D: 

   Event 21: Negative Response Sent on Connection <value> (SENSE=400D)
where 400D = CD Not Supported: The Change-Direction indicator was set, 
             but is not supported
SNA Server can be configured to work around this host problem by setting the NO400D registry value as defined below. However, even with this option set, SNA Server still does not allow an LUA (RUI or SLI) application to set the CD bit on a full duplex LU0 session, since this is a protocol violation.

MORE INFORMATION

When a host application initiates an LU0 session with full duplex send/receive mode (by setting bit 0-1 to "00" in Byte 7 of the BIND message), this indicates that the Change Direction (CD) bit is not to be used on the session. The Change Direction bit is only used on half-duplex sessions to indicate which end has direction to send on a session.

However, some host applications may still set the CD bit on a full duplex session, though this is a protocol violation. However, it may not be possible to fix the host application, so SNA Server will ignore this message by enabling the following registry key: 

   HKEY_LOCAL_MACHINE/SYSTEM/CurrentControlSet/Services/
   SnaServr/Parameters/

   NO400D: REG_SZ: YES
This causes SNA Server to ignore any messages received on an LU0 full duplex session which has the CD bit set. However, the LUA (RUI or SLI) application running on SNA Server is still not allowed to set the CD bit when sending messages to the host on a full duplex LU0 session, since this is a protocol violation.

NOTE: For information about the BIND command, see the IBM SNA Formats Guide, IBM part number GA27-3136.

Additional query words:
Keywords : prodsna snalua kberrmsg kbnetwork kbprb
Version : 2.11 3.00
Platform : WINDOWS

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Last reviewed: November 5, 1997
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