Article ID: 275896
Article Last Modified on 2/20/2007
APPLIES TO
- Microsoft Host Integration Server 2000 Standard Edition
- Microsoft SNA Server 4.0
- Microsoft SNA Server 3.0 Service Pack 2
- Microsoft SNA Server 3.0 Service Pack 3
- Microsoft SNA Server 3.0 Service Pack 4
- Microsoft SNA Server 4.0
- Microsoft SNA Server 4.0 Service Pack 1
- Microsoft SNA Server 4.0 Service Pack 2
- Microsoft SNA Server 4.0 Service Pack 3
This article was previously published under Q275896
SYMPTOMS
TN3270(E) clients may intermittently lose their session to the host application. This problem occurs when the SNA Server TN3270 client is used to communicate with an SAS Statistical Analysis application.
When the failure occurs, the emulator may display a message that indicates that a "BRACKET ERROR" was encountered; the actual format of the message may vary depending on the TN3270(E) emulator that is used.
The SNA application LUA API traces that are gathered during an occurrence of the failure indicate the following return codes on the failed session:
prim_rc=0x1400 (LUA_UNSUCCESSFUL) sec_rc=0x00000320 (LUA_BRACKET)
In addition, the Microsoft Windows NT application event log may show the following events at the time that the failure occurs:
EventID : 603
Source : TN3270 Server
Description : TN3270(E) session with client at xxxx.xxxx.xxxx.xxxx (port xxxx)using LU ABCD terminated abnormally because:
TN3270E Service Error 505
SNA API verb WRITE failed. Failure described as:
RUI Write verb has completed with primary rc of Unsuccessful and secondary rc of Bracket Protocol Error.
Explanation : A TN3270(E) client session was terminated abnormally
EventID : 309
Source : TN3270 Server
Description : WRITE failed with LUA_UNSUCESSFUL / LUA_BRACKET for xxxx.xxxx.xxxx.xxxx(port xxxx)
Explanation : An SNA API call failed
CAUSE
When this problem occurs, SNA Server receives data from the host with the CD CD (Change Direction) and DR1 (Definite Response) bits set, which it passes through TN3270 server to the client.
However, the user of the TN3270 client is typing ahead and as a result the client then sends some data to the TN3270 server without first sending an ACK for the previous data frame from the host that had the DR1 bit set. This causes SNA Server to reject this new data frame with a sense code of 200D.
RESOLUTION
To resolve this problem, obtain the latest service pack for SNA Server 4.0. For additional information, click the following article number to view the article in the Microsoft Knowledge Base:
215838 How to Obtain the Latest SNA Server Version 4.0 Service Pack
WORKAROUND
Microsoft recommends that customers use an emulator that adheres to the IBM TN3270 protocol specification.
STATUS
Microsoft has confirmed that this is a problem in Microsoft SNA Server version 4.0, SP1, SP2 and SP3.
This problem was first corrected in SNA Server 4.0 Service Pack 4.
Additional query words: HIS 2000
Keywords: kbbug kbfix kbsna400presp4fix kbqfe kbsna400sp4fix KB275896
