TPs Can't Be Invoked On Windows 95/NT Clients if One TP Ends (180537)

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

The 084C0000 refers to AP_TRANS_PGM_NOT_AVAIL_NO_RETRY.

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, 2.11 SP2, 3.0, 3.0 SP1, 3.0 SP2, and 4.0.

This problem was corrected in the latest SNA Server versions 3.0 and 4.0 U.S. Service Packs. For information on obtaining these Service Packs, query on the following word in the Microsoft Knowledge Base (without the spaces):

S E R V P A C K

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:

166623 SNA Server Rejects FMH-5 Attach Intended for TP on NT Client

170071 Invokable TP Timeout May Occur with Non-queued Operation