RUI Library Terminates RUI Session When PIU Has Not Been Sent

The information in this article applies to:

• Microsoft SNA Server, versions 2.11 Service Pack 1 and 3.0

SYMPTOMS

Under certain conditions, an LUA session may terminate unexpectedly with the following error message:

   Event ID: 1954
   Source:   SNA RUI Application
   Description: RUI internal logic error for LU <name>, code <value>

CAUSE

When the SNA Server service informs the RUI library that a Path Information Unit (PIU) has not been sent due to some problem (such as a bracket error), the RUI library terminates the RUI session. RUI internal logical error 1954 is logged in the application Event Log.

RESOLUTION

A fix is available to correct this problem.

STATUS

Microsoft has confirmed this to be a problem in Microsoft SNA Server versions 2.11 Service Pack 1 and 3.0. A supported fix is now available, but is not fully regression-tested and should be applied only to systems experiencing this specific problem. Unless you are severely impacted by this specific problem, Microsoft recommends that you wait for the next Service Pack that contains this fix. Contact Microsoft Technical Support for more information.

MORE INFORMATION

The RUI library posts RUI_WRITE as complete once it has passed the data to the SNA Server service, instead of waiting for the SNA Server service to actually process the data. In this situation, it is possible that the PIU has not yet been sent. For example, this may be the case due to a race condition with the host application. When the SNA Server service informs the RUI library that the PIU has not been sent, the RUI library terminates the RUI session because it was already informed that the RUI_WRITE was completed successfully.