Q224388: SMS: Slownet Determines Network Speed at Logon
Article: Q224388
Product(s): Microsoft Systems Management Server
Version(s): winnt:2.0
Operating System(s):
Keyword(s): kbtool dun kbsms200 kbDialUp
Last Modified: 06-AUG-2002
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The information in this article applies to:
- Microsoft Systems Management Server version 2.0
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SUMMARY
=======
Slownet.exe is called at logon in SMSLS to determine the network connection
speed between the client and the logon point. Depending on the client platform,
the file to which Slownet maps can be any of the following files:
Slwnt32.exe for Windows NT (Intel) and Windows 95/98 clients
Slwnt32a.exe for Windows NT (Alpha)
Slwnt16.exe for 16-bit Windows clients
Slownet's calculation of connection speed is a snapshot that varies substantially
depending on a number of factors including, but not limited to, maximum
connection speed, line quality, and current network load. The Windows 32
Slownet.exe uses the Win32 MultinetGetConnectionPerformance API call. This API
calls asks the transport layer (for example, IP) to tell it how fast the
connection is. SMS does not have any control over the return value from this API
call. It could report a significantly slower speed than the actual connection,
which can frequently be attributed to a slow network (not just a slow RAS
connection).
If Slownet detects that a connection speed is less than 40 KB, the client
installation routine is bypassed and the client is not installed.
Slownet can be used for the following tasks:
- Determining the connection speed between a client and its server
- Prompting the user to continue with the client installation despite a slow
network connection being detected
- Detecting whether the client is logging on to the network over RAS and
bypassing the client installation if RAS is detected at all (similar to the
Checkras utility's functionality)
In some circumstances, you may want to change the default threshold that Slownet
uses to determine whether or not a client will be installed. If the threshold is
lowered, keep in mind that the client installation may take a long time and may
cause the user to wait at logon for components to be installed or upgraded.
If it is necessary to force clients to install over a slow link, consider the
following options:
- Changing the threshold speed specified in the logon script
- Customizing the logon script to prompt the user whether or not to run the SMS
client installation (after determining it is a slow link)
- Removing all references to the Slownet.exe and Snboot.exe calls from the
logon script
- Adding a custom determination in the logon script (for example, "Is this user
a member of the 'remote salespeople' group and therefore should always run
SMS")
- Using the Systems Management Installation wizard (Smsman.exe)
- Using alternate discovery and installation methods such as Network Discovery
or Windows NT Remote Client Installation
To determine exactly what Slownet is doing, you can run Slownet with the /v
parameter to print verbose output to the screen.
MORE INFORMATION
================
Manually Determining the Connection with Slownet
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You can use Slownet as a command-line utility on the client computer. If the
Slownet.exe file is not already on the client, copy the appropriate
Slwnt<xx>.exe file to the client computer. Run the following command at a
command prompt:
<exename> \\<computername>\<share><newspeed> /verbose
For example:
slownet \\siteserver1\share 10000 /v
This command reports your calculated speed and tells you if your link is faster
or slower than 10 Kbps.
To determine if the calculated speed is faster or slower than 40 Kbps (by
default, Slownet detects for at least 40 Kbps), run the following command from a
command prompt:
slwnt32 \\siteserver1\share /v
Note that if the server or share is not available, Slownet assumes a fast link
and returns the following message:
Remote Name is \\siteserver1\c$
MultinetGetConnectionPerformance returned error: 2250. Defaulting to RAS
Check
No RAS connections are present, assuming fast link
Modifing Slownet in the SMSLS Logon Script
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If you want to modify the Slownet threshold, back up the Ssmsls.bat file in the
Sms\Data\Nt_logon folder to Smsls.org. Then, modify the following lines in the
Sms\Data\Nt_logon directory\Smsls.bat file:
- :OK_TO_PROCEED
Replace: %SMS_LOCAL_DIR%\MS\SMS\CORE\BIN\Slownet.exe %0
With: %SMS_LOCAL_DIR%\MS\SMS\CORE\BIN\Slownet.exe %0 1000
- :SLOWNETUSER
Replace: %SMS_LOCAL_DIR_USER%\MS\SMS\CORE\BIN\Slownet.exe %0
With: %SMS_LOCAL_DIR_USER%\MS\SMS\CORE\BIN\Slownet.exe %0 1000
- :SLOWNETTEMP
Replace: %TEMP%\Slownet.exe %0
With: %TEMP%\Slownet.exe %0 1000
- :SLOWNETSERVER
Replace: %0\..\SNBOOT.exe
With: %0\..\SNBOOT.exe 1000
NOTE: The server and share names must be in all lowercase letters. This example
presumes a minimal connection speed of 1000 bps, but this value can be any value
less than 40,000.
If the Smsls.bat file is changed after the creation of the logon point, copy the
updated Smsls.bat file to the %Windir%\System32\Repl\Export\Scripts and
%Windir%\System32\Repl\Import\Scripts folders on the logon server.
Slownet with RAS
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When you dial in over RAS, the speed Slownet detects may be lower than the
dial-up status indicator, as indicated in the following table.
Client modem RAS server modem Dial-up reports Slownet reports
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USR 33.6 USR 33.6 28.8 to 33.6 3500
IBM 56k USR 33.6 28.8 to 57.6 3500 to 3800
IBM 56k USR 56K 57.6 to 115k 11500 to 11600
When a RAS client runs the SMSLS batch file at logon, Slownet.exe is copied to
the client and run. If it detects that the connection speed is slower than 40
KB, the client is not installed.
It is possible to use Slownet to only determine whether a client is using a RAS
connection. To do so, substitute the connection speed with 0. For example:
slownet \\siteserver1\share 0 /v
If RAS is detected, the return code is 0.
If you want to prevent the client from having any files (including Slownet)
installed at logon, you can use the Checkras utility included in the BackOffice
Resource Kit. Checkras.exe checks for RAS connections on the client instead of
trying to determine the link speed. You can use the Checkras.exe utility in your
logon script to determine whether or not a user is connected by a RAS
connection, and then include commands in your logon script based on the results
returned by Checkras.exe.
The following sample Windows NT domain logon script uses Checkras.exe:
@echo off
echo Checking for existence of RAS files
if exist %windir%\system32\RASAPI32.DLL goto ras_status
if exist %windir%\system\RASAPI32.DLL goto ras_status
goto notras
:ras_status
echo Checking for existence of Checkras.exe
if exist %windir%\checkras.exe goto yes_checkras
copy \\server\netlogon\checkras.exe %windir%
:yes_checkras
echo Checking for RAS connection
%windir%\checkras
if errorlevel 1 goto ras
echo This is not a RAS connection
goto end
:notras
echo RAS is not installed on this system
goto end
:ras
echo RAS connection detected
REM Enter RAS-specific command here.
:end
NOTE: Windows NT 3.51 clients are not supported with Systems Management Server
2.0 over RAS. If Windows NT 3.51 clients will be logging in over RAS, Checkras
must be used to prevent them from installing the SMS client.
For additional information about client installation, click the article number
below to view the article in the Microsoft Knowledge Base:
Q202338 SMS: Pre-stage Clients To Avoid Bandwidth Contention In Install
Additional query words: prodsms relnote SMS2 netspeed
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Keywords : kbtool dun kbsms200 kbDialUp
Technology : kbSMSSearch kbSMS200
Version : winnt:2.0
Issue type : kbinfo
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