802.2 Link Service Hangs APPC Program or Causes Event ID 592

• Microsoft SNA Server for Windows NT, version 2.11

SYMPTOMS

When you download data from a host computer using an APPC program with 4K RU sizes (pacing of 8), one or more of the following symptoms occur:

• The following event appears in the application log:

        Event ID 592
        Descrition: Receive_Allocate timed out. No incoming allocate was
        accepted within the configured timeout period.
  

• The APPC program freezes.

CAUSE

When SNA server detects that DLC.SYS is in a local busy state, the 802.2 link service queries DLC.SYS once to see whether it has enough buffers to clear it, but the 802.2 link service fails to continue querying if the first query is unsuccessful.

This is a trace of the problem:

   (linkint.trc)
   |00000027.00000093 TRC_W  asy-wr writeptr now 24, linktype 4
   |00000027.00000093 a4ucc  completed READ - index = 0, rc = 0
   |00000027.00000093 a4ucc  DLC status - code = 1
   |00000027.00000093 a4ucc  entering local busy due to buffer shortage
   |00000027.00000093 a4ugb  get a DRB - command = 1e
   |00000027.00000093 a4ugb  get a general DRB
   |00000027.00000093 a4ugb  got a DRB 00073630 command 1e

RESOLUTION

To resolve this problem, install the fix mentioned below. The new 802.2 link service retries the query about every 0.2 seconds. Microsoft has updated the file SNADLC.DLL to correct this problem.

To work around this problem if your program hangs, deactivate the LU on both the host and in SNA Server.

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