DOCUMENT:Q236316  16-MAY-2002  [winnt]
TITLE   :Performance Improvement for Redirector/Server Connections
PRODUCT :Microsoft Windows NT
PROD/VER:winnt:4.0
OPER/SYS:
KEYWORDS:kbWinNT4sp6fix

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The information in this article applies to:

 - Microsoft Windows NT Server version 4.0, Terminal Server Edition 
 - Microsoft Windows NT Server version 4.0 
 - Microsoft Windows NT Workstation version 4.0 
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SYMPTOMS
========

Programs that perform numerous small file operations, such as locking and
unlocking files or writing small records, may experience slow performance.

CAUSE
=====

This problem occurs because the combination of "Nagling" (a TCP concept
described in the Microsoft Knowledge Base and white papers) and TCP delayed
acknowledgment can cause unnecessary network delay when numerous small file
operations are outstanding between a client and server. More details on Nagling
are available at the following Microsoft Web site:

   ftp://ftp.microsoft.com/bussys/winnt/winnt-docs/papers/TCPIMP2.EXE

RESOLUTION
==========

Windows NT Server or Workstation 4.0
------------------------------------

To resolve this problem, obtain the latest service pack for Windows NT 4.0 or the
individual software update. For information on obtaining the latest service
pack, please go to:

 - http://www.microsoft.com/windows/servicepacks/

-or-

 - Q152734 How to Obtain the Latest Windows NT 4.0 Service Pack

For information on obtaining the individual software update, contact Microsoft
Product Support Services. For a complete list of Microsoft Product Support
Services phone numbers and information on 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: The optimization that is described in this article may lead to a
performance decrease in some scenarios. This has been observed when a computer
with the fix installed accesses a server on the network that does not have the
fix. When the client performs many file locks and small reads, performance may
be slower than between two computers without the fix. In this case, Microsoft
recommends deploying SP6a on all the computers. If deploying SP6a is not an
option, the following fix is still available that incorporates the change as a
post-SP5 hotfix.

The English version of this fix should have the following file attributes or
later:

   Date      Time     Size      File name   Platform
   --------------------------------------------------
   06/28/99  01:10p   123,120   Netbt.sys   x86
   06/28/99  01:09p   224,144   Netbt.sys   Alpha


Windows NT Server 4.0, Terminal Server Edition
----------------------------------------------

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

   Q152734 How to Obtain the Latest Windows NT 4.0 Service Pack


STATUS
======

Microsoft has confirmed this to be a problem in Windows NT 4.0 and Windows NT
Server 4.0, Terminal Server Edition. This problem was first corrected in Windows
NT Server version 4.0, Terminal Server Edition Service Pack 6.

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

The Netbt.sys driver has been modified to disable nagling in the TCP stack for
NetBT connections.

Additional query words: nagle tcpip netbt

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Keywords          : kbWinNT4sp6fix 
Technology        : kbWinNTsearch kbWinNTWsearch kbWinNTW400 kbWinNTW400search kbWinNT400search kbWinNTSsearch kbWinNTS400search kbWinNTS400 kbNTTermServ400 kbNTTermServSearch
Version           : winnt:4.0
Hardware          : ALPHA x86
Issue type        : kbbug
Solution Type     : kbfix

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Copyright Microsoft Corporation 2002.