TPs Can't Be Invoked On Windows 95/NT Clients if One TP Ends

• Microsoft SNA Server, versions 2.0, 2.1, 2.11, 2.11SP1, 2.11SP2, 3.0, 3.0SP1, 3.0SP2, and 4.0

SYMPTOMS

If multiple instances of the same invokable APPC/CPI-C TP are running on a SNA Server Client for Windows 95 or Windows NT, the active TPs cannot be invoked if one instance of the TP ends for any reason.

SNA Server will log the following event in the Windows NT Application Event Log when attempting to invoke one of the remaining active TPs on the Windows 95 or Windows NT client:

   Event ID: 60
   Source: SNA Server
   Description: Failed to invoke APPC TP <TP Name>, sense data = 084C0000

CAUSE

When an invokable APPC TP is started on a client, SnaBase sends an update message to the client's sponsor SNA Server. The SNA Server adds the TP to its local service table; this entry is used for routing incoming DLOAD messages to the client. When the TP ends, the client SnaBase sends another update message to the sponsor server asking the SNA Server to remove the TP from its service table. These messages, both add and remove, are sent for each instance of the TP running on the client. The SNA Server only keeps one instance of the TP in its service table no matter how many instances are running on the client. When one instance of the TPs ends, the SNA Server marks the TP listed in the service table as inactive, which means none of the other TPs on the client can be invoked by the partner TP.

STATUS

Microsoft has confirmed this to be a problem in SNA Server version 2.0, 2.1, 2.11, 2.11 SP1, 3.0, 3.0 SP1, and 4.0.

Microsoft has also confirmed this to be a problem in SNA Server version 2.11 SP2 and 3.0 SP2. A supported fix is now available for SNA Server 2.11 SP2 and 3.0 post-SP2, but has not been 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

With the fix applied, the SNA Server Clients for Windows 95 and Windows NT are updated so that the update message to remove a TP from the service table on the SNA Server is only sent after the last instance of the TP ends.

NOTE: There are other possible causes for this event, which are not related to this particular issue. For additional information, please see the following articles in the Microsoft Knowledge Base:

   Article-ID: Q166623
   Title     : SNA Server Rejects FMH-5 Attach Intended for TP on NT Client

   Article-ID: Q170071
   Title     : Invokable TP Timeout May Occur with Non-queued Operation

Keywords          : kbbug2.00 kbbug2.10 kbbug2.11 kbbug2.11.sp1 kbbug2.11.sp2 kbbug3.00 kbbug3.00.sp1 snaappc snacpic snaprog snatp snawin95 snawinnt kbbug3.00.sp2 kbbug4.00 kbnetwork
Version           : WINDOWS:2.0,2.1,2.11,2.11SP1,2.11SP2,3.0,3.0SP1,3.0SP2,4.0
Platform          : WINDOWS
Issue type        : kbbug
Solution Type     : kbfix