Article ID: 160576
Article Last Modified on 2/19/2007
APPLIES TO
- Microsoft SNA Server 2.0
- Microsoft SNA Server 2.1
- Microsoft SNA Server 3.0
- Microsoft SNA Server 3.0 Service Pack 4
- Microsoft SNA Server 4.0
- Microsoft SNA Server 4.0 Service Pack 4
- Microsoft Host Integration Server 2000 Standard Edition
- Microsoft Host Integration Server 2000 Service Pack 1
- Microsoft Windows NT 4.0
This article was previously published under Q160576
SYMPTOMS
SNA Server clients using 3270 display sessions are returned to the SSCP (VTAM Signon) screen unexpectedly while actively working in a host application. The SNA Server may log one or more of the following events in the Windows NT Application Event Log when this problem occurs:
CAUSE
This has only been reported on SNA Servers with 802.2 connections to IBM 3174 Control Units on Ethernet networks. The problem occurs because a 3174 Ethernet gateway may send a duplicate SNA sequence number to the SNA Server when the 3174 is handling an SNA frame between 1490 and 1493 bytes in size. This leads to a condition where a frame may be re-sent by the 3174 causing the symptoms discussed previously. In addition, the problem only occurs if the 3174 is running 3174 Microcode Level C6.1 or C6.2.
RESOLUTION
A fix for this problem is available from IBM. Contact IBM support and request IBM 3174 PTR #B27E.
MORE INFORMATION
For information about how to contact IBM, query in the Knowledge Base for one of the following articles:
65416 Hardware and Software Third-Party Vendor Contact List, A-K
60781 Hardware and Software Third-Party Vendor Contact List, L-P
60782 Hardware and Software Third-Party Vendor Contact List, Q-Z
The third-party products discussed here are manufactured by vendors independent of Microsoft; we make no warranty, implied or otherwise, regarding these products' performance or reliability.
Additional query words: prodsna
Keywords: kbnetwork KB160576