Windows NT LUA Application Hangs After 32767 SLI_SEND Commands

• Microsoft SNA Server for Windows NT, version 2.11

SYMPTOMS

When you run an LUA/SLI application on Windows NT, the application stops responding (hangs) after issuing 32767 SLI_SEND commands. The next SLI_SEND command is never sent to the Host.

CAUSE

The SLI_SEND hangs because an internal counter in the RUI library is being incremented for each send, but never being decremented. Because the counter is a 2 byte integer, it is wrapping to zero after 32,767 sends.

If the SNA Server RUI library and the server are receiving large inbound RUs from the host, then the RUI library never decrements its internal send credit. This can cause two possible errors:

• If the SNA Server does return a credit message after receiving data from the RUI library, eventually the RUI library's send credit is incremented so much that it becomes zero, causing the RUI library to stop sending data because it thinks it has run out of credit.
• If the RUI application is pumping data to the node (for example, transferring a file to the host), then it floods the node, because the RUI library always believes that it has enough credit.

RESOLUTION

Microsoft has updated the files, WINRUI.DLL ,for 16-bit clients, and WINRUI32.DLL, for 32-bit clients, and ACSRUI.DLL for OS/2 clients to correct this problem.

STATUS

Microsoft has confirmed this to be a problem in SNA Server for Windows NT. This problem was corrected in the latest SNA Server for Windows NT, 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