SNA Server Fails to Send Data to DSPU After an Outage

• Microsoft SNA Server for Windows NT, version 2.11 SP2, 3.0 and 3.0 SP1

SYMPTOMS

Under certain circumstances, like a link outage between SNA Server and a Downstream System, SNA Server may fail to send host data to the downstream System on the SSCP-LU session. Sessions or applications on the downstream system then seem to hang, waiting for data.

CAUSE

We recently introduced a queue within the SNA Server service to ensure that requests from the Host on the LU-SSCP session were handled serially. Unfortunately in one case this queue is not cleared. The particular case is when the SNA Server service receives a request from the host when the downstream session or application is not ready to receive data. The EXR or -RSP generated was not routed through the DFC layer (where the queue was managed).

STATUS

Microsoft has confirmed this to be a problem in SNA Server version 2.11 Service Pack 2, 3.0 and 3.0 Service Pack 1. A fix to this problem is in development, but has not been regression-tested and may be destabilizing in production environments.

Microsoft does not recommend implementing this fix at this time. Contact Microsoft Product Support Services for more information on the availability of this fix.