Q262473: LU 6.2 Data Compression Fails When Initiated by Host System

Article: Q262473
Product(s): Microsoft SNA Server
Version(s): WINDOWS:4.0,4.0 SP1,4.0 SP2,4.0 SP3
Operating System(s): 
Keyword(s): sna4 kbsna400sp1 kbsna400sp2 kbsna400sp3 kbSNA400sp4fix kbSNA400PreSP4fix
Last Modified: 08-DEC-2000

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The information in this article applies to:

- Microsoft SNA Server, versions 4.0, 4.0 SP1, 4.0 SP2, 4.0 SP3 
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SYMPTOMS
========

SNA Server does not use LU 6.2 data compression when the BIND is a host
initiated, non-extended BIND. Compression is not used even though it has been
configured on both the connection and on the APPC mode definition.

CAUSE
=====

When SNA Server negotiates LU 6.2 compression, it checks the level of
compression that is configured on the mode entry and the level of compression
that is configured on the connection. It obtains this information from a
connection record in an internal connection table.

This problem occurs because SNA Server is incorrectly reading the connection
record, and therefore, it obtains the wrong value for compression support.
Because of this, SNA Server does not accept the host systems request for data
compression.

RESOLUTION
==========

To resolve this problem, obtain the latest service pack for SNA Server 4.0. For
additional information, please see the following article in the Microsoft
Knowledge Base:

  Q215838 How to Obtain the Latest SNA Server Version 4.0 Service Pack



WORKAROUND
==========

This problem does not occur when SNA Server initiates the BIND with the host. In
most scenarios, setting an Automatic Activation Limit on the APPC mode
definition eliminates this problem by forcing SNA Server to initiate the BIND
with the host.

STATUS
======

Microsoft has confirmed this to be a problem in Microsoft SNA Server version
4.0, 4.0 SP1, 4.0 SP2, and 4.0 SP3.

This problem was first corrected in SNA Server 4.0 Service Pack 4.

MORE INFORMATION
================

For LU 6.2 data compression to work on SNA Server, it needs to be configured on
both the connection and the APPC mode definition. This is also true for 3270/LUA
LU data compression, which needs to be configured on both the connection and the
LU.

For additional information on how to configure SNA Server for compression when
non-extended BINDs are used, click the article number below to view the article
in the Microsoft Knowledge Base:

  Q266091 Configuring For Host Compression When Using Non-Extended BINDs

Additional query words:

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Keywords          : sna4 kbsna400sp1 kbsna400sp2 kbsna400sp3 kbSNA400sp4fix kbSNA400PreSP4fix 
Technology        : kbAudDeveloper kbSNAServSearch kbSNAServ400 kbSNAServ400SP1 kbSNAServ400SP2 kbSNAServ400SP3
Version           : WINDOWS:4.0,4.0 SP1,4.0 SP2,4.0 SP3
Issue type        : kbbug
Solution Type     : kbfix

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