| layout | title | permalink |
|---|---|---|
page |
Q312853: FMH-5 Attach Message Routed to TP Even if Local LU Doesn't Match |
/kb/312/Q312853/ |
{% raw %}
Article: Q312853
Product(s): Microsoft SNA Server
Version(s): 4.0 SP3,4.0 SP4
Operating System(s):
Keyword(s): kbDSupport kbsna400sp3 kbsna400sp4
Last Modified: 11-JUN-2002
-------------------------------------------------------------------------------
The information in this article applies to:
- Microsoft SNA Server, versions 4.0 SP3, 4.0 SP4
-------------------------------------------------------------------------------
IMPORTANT: This article contains information about modifying the registry. Before you modify the registry, make sure to back it up and make sure that you understand how to restore the registry if a problem occurs. For information about how to back up, restore, and edit the registry, click the following article number to view the article in the Microsoft Knowledge Base:
Q256986 Description of the Microsoft Windows Registry
SYMPTOMS
========
Microsoft SNA Server may route an incoming FMH-5 Attach message to a Transaction
Program (TP) even though the invokable TP is registered with a Local Logical
Unit (LU) that does not match the Local LU specified in the FMH-5 Attach
message.
RESOLUTION
==========
A supported fix is now available from Microsoft, but it is only intended to
correct the problem described in this article and should be applied only to
systems experiencing this specific problem. This fix may receive additional
testing at a later time, to further ensure product quality. Therefore, if you
are not severely affected by this problem, Microsoft recommends that you wait
for the next Microsoft SNA Server version 4.0 service pack that contains this
fix.
To resolve this problem immediately, contact Microsoft Product Support Services
to obtain the fix. For a complete list of Microsoft Product Support Services
phone numbers and information about support costs, please go to the following
address on the World Wide Web:
http://support.microsoft.com/default.aspx?scid=fh;EN-US;CNTACTMS
NOTE: In special cases, charges that are normally incurred for support calls may
be canceled, if a Microsoft Support Professional determines that a specific
update will resolve your problem. Normal support costs will apply to additional
support questions and issues that do not qualify for the specific update in
question.
The English version of this fix should have the following file attributes or
later:
+---------------------------------+
| File name | Date | Time |
+---------------------------------+
| snadmod.dll | 8/10/2001 | 12:09 |
+---------------------------------+
NOTE: Because of file dependencies, the most recent fix that contains the above
files may also contain additional files.
STATUS
======
Microsoft has confirmed this to be a problem in SNA Server versions 4.0 SP3, 4.0
SP4.
NOTE: This problem does not exist in Microsoft Host Integration Server 2000.
MORE INFORMATION
================
The following is an example of the problem described in the "Symptoms" section
of this article.
WARNING: If you use Registry Editor incorrectly, you may cause serious problems
that may require you to reinstall your operating system. Microsoft cannot
guarantee that you can solve problems that result from using Registry Editor
incorrectly. Use Registry Editor at your own risk.
+-------------------------------------------+
| SNA Client | Invokable TP Name | Local LU |
+-------------------------------------------+
| Client1 | APINGD | LUPINGD |
+-------------------------------------------+
| Client2 | APINGD | LUPINGD2 |
+-------------------------------------------+
If Client2 becomes unavailable after successfully registering TP APINGD, an SNA
Server 4.0 SP3 or 4.0 SP4 system will route an incoming FMH-5 Attach message for
APINGD to Client1, even though the request specifies LUPINGD2 as the Local LU
alias.
The correct behavior for the example described here is for the SNA Server to
reject the FMH-5 Attach unless an invokable TP is registered with a TP Name of
APINGD that does not have an associated Local LU alias.
The following information provides an overview of how SNA Server and Host
Integration Server (HIS) 2000 handle the FMH-5 Attach messages intended for
invokable TPs. This information can also be found in the APPC Programmer's Guide
included with the SNA Server and HIS 2000 software developer kits (SDKs).
When SNA Server receives an FMH-5 Attach message in an SNA subdomain in which
multiple invokable TPs are running, SNA Server must decide where to route the
FMH-5 Attach message for eventual execution of the TP. Specific control over the
routing of FMH-5 Attach messages can be controlled in a number of ways. The
following are the three ways that invokable TPs can be arranged in an SNA
subdomain:
- Unique TP name for each TP:
In this case, each invokable TP running on an SNA client or SNA Server
computer will have a unique TP name. The FMH-5 Attach message includes the
name of the TP that it is intended for; therefore, SNA Server will be able to
route the Attach message to the system that has registered that specific TP
name.
- TP name not unique; Local LU alias unique:
In this case, each invokable TP has the same name, but each is associated with
a unique Local LU alias. SNA Server knows which LU 6.2 session that the FMH-5
Attach message is using; therefore, it knows which local and remote LUs are
being used. SNA Server will route the request to not only the correct TP name
but also to the correct Local LU alias for the intended invokable TP.
- TP name not unique; Local LU alias unspecified:
In this case, each TP is registered with the same TP name, and none are
associated with specific Local LU aliases. This is the arrangement that is
used when it does not matter which system executes the TP request.
In addition, you can use the following registry entries in conjunction with the
preceding scenarios to further control the routing of FMH-5 Attach messages:
- DloadMatchTPOnly:REG_SZ:{ YES | NO }
When this variable is set to YES, the comparison between a FMH-5 Attach
message for a TP and the list of invokable TPs is based only on the TP name.
Otherwise, the comparison is based on both the requested TP name and the
requested LU alias. This variable affects the SNA servers on which it is set,
but does not affect other SNA servers.
To use a specific LU alias, you can configure invokable TPs through a registry
or environment variable on the system in which the TP is located. If you
configure the invokable TP in this way, the setting of DloadMatchTPOnly will
control whether the LU alias is used in comparisons against incoming
requests. If the invokable TP is not configured to use a specific LU alias,
there cannot be a mismatch (regardless of the setting of DloadMatchTPOnly),
no matter which LU alias an incoming request is using. With such TPs,
matching is affected only by the TP name.
The default value is NO, meaning that the comparison uses both the TP name and
LU alias (when the LU alias has been configured for the invokable TP).
- DloadMatchLocalFirst:REG_SZ:{ YES | NO }
When this variable is set to NO, the comparison between a request for a TP and
the list of available invokable TPs is performed without regard for the
location of the TP. Otherwise, invokable TPs on the local SNA server are
considered first for a potential match. This variable affects the SNA server
on which it is set, but not other SNA servers in the subdomain.
The default value is YES, meaning that invokable TPs on the local SNA server
are considered first for a potential match.
These registry parameters are not defined by default, so they need to be added
under the following location if the default values need to be changed:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SnaServr\Parameters
Additional query words:
======================================================================
Keywords : kbDSupport kbsna400sp3 kbsna400sp4
Technology : kbAudDeveloper kbSNAServSearch kbSNAServ400SP3 kbSNAServ400SP4
Version : :4.0 SP3,4.0 SP4
Issue type : kbbug
Solution Type : kbfix
=============================================================================
{% endraw %}