Occasional Event 23 Outages With a Microgate SDLC Adapter

• Microsoft SNA Server version 2.1, 2.11, and 2.11 SP1

SYMPTOMS

An SDLC connection from SNA Server may drop to a Pending state occasionally when using a Microgate SDLC adapter. When this occurs, SNA Server may log a message similar to the following in the Windows NT Application Event Log:

   Event ID: 23
   Description: Connection <connection_name> using Link Service
   <link_service_name> failed.

   Qualifier = 25

CAUSE

The Ibmsync.sys driver that is used by the Microgate SDLC link service was found to have a scheduling window that could cause occasional connection outages as described above. There were two problems found and corrected in the Ibmsync.sys driver:

• The problem caused messages to be lost or received out of order, but should only occur on high-speed SDLC lines.
• The second problem may cause messages to be delayed in processing until another message arrives. This has only been seen when running at 2Mbps over the SDLC adapter, but again the window to hit the problem was there when running at lower speeds.

RESOLUTION

The Ibmsync.sys has been updated to correct the two problems described above.

STATUS

Microsoft has confirmed this to be a problem in SNA Server versions 2.1, 2.11, and 2.11 SP1. This problem was corrected in the latest Microsoft SNA Server 2.11 U.S. Service Pack. For information on obtaining the service pack, query on the following word in the Microsoft Knowledge Base (without the spaces):

   S E R V P A C K