Article ID: 142692 - View products that this article applies to.
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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:
(http://support.microsoft.com/kb/256986/EN-US/ )Description of the Microsoft Windows Registry
This article lists the modifications that have to be made to your computers deployed in a WAN environment, if you want to minimize the traffic over the routers. This information applies only to Windows NT 4.0 and Windows NT 3.51 Service Pack 5.
This information can become very useful if, for example, you are using ISDN lines rather than leased lines. When using ISDN, each frame sent across the ISDN line may establish a new connection and, therefore, costs money. Thus, the operating cost of your ISDN lines can become very high.
Because much of the traffic is generated by Windows NT domain controllers, this traffic can be dramatically reduced using these modifications.
CAUTION: The parameter change included in this article has not been extensively tested in large installations. Microsoft cannot guarantee that modification of registry settings as recommended herein will accomplish the objective described in this article under all circumstances and in all configurations.
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.
Assume that your Windows NT systems have been spread across several sites interconnected by routers, and consider two typical cases:
The License Service May Generate Traffic Every 15 MinutesThe License service performs licensing replication. Data moves from BDCs and member servers to the PDCs, and then, optionally, from the PDCs to an enterprise server, which maintains licensing information across the whole network.
This replication, by default, is performed one time every 24 hours. If, for some reason, the BDC cannot connect to the license service on the PDC, the BDC will continue to attempt replication one time every 15 minutes until it is successful.
Reducing Exchange of Browse ListsNote This setting also applies to Windows Server 2008.
Every MasterPeriodicity time interval (every 12 minutes, by default), the master browsers, which are the BDCs, try to contact the domain master browser, the PDC, to exchange their browse lists.
This parameter can be changed in the registry of all the BDCs:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Browser\ParametersFor additional information about this parameter, click the article number below to view the article in the Microsoft Knowledge Base:
Value : MasterPeriodicity DWORD number in seconds
Default : 720
134985To optimize the traffic on your WAN lines, increase the value above on all BDCs.
(http://support.microsoft.com/kb/134985/EN-US/ )Browsing & Other Traffic Incurs High Costs Over ISDN Routers
SAM Replication Between a PDC and Its BDCsThe SAM replication is controlled by Netlogon on the PDC. The following registry value defines the typical pulse frequency (in seconds):
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\NetLogon\ParametersFor additional information, click the article number below to view the article in the Microsoft Knowledge Base:
Value : Pulse REG_DWORD 60 to 172800 seconds (48 hours)
Default : 300
150350All SAM/LSA changes made within this time are bundled together. After this period has elapsed, a pulse is sent to each BDC needing the changes. No pulse is sent to a BDC that is up-to-date.
(http://support.microsoft.com/kb/150350/EN-US/ )NetLogon Maximum Value of Pulse Should Exceed 3600
Increasing this value on the PDC reduces the number of replications between the PDC and the BDCs. Nevertheless, the SAM changes are propagated less quickly from the PDC to the BDCs. You must choose a balance between infrequent replication that may increase the number of connections to a PDC to validate changed passwords and frequent replication that may generate excessive ISDN traffic.
The Netlogon PulseMaximum parameter has to be changed:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\NetLogon\ParametersIt defines the maximum pulse frequency (in seconds). Every BDC will be sent at least one pulse at this frequency, whether its database is current or not.
Value : PulseMaximum REG_DWORD 60 to 172800 seconds (48 hours)
NOTE: The replication takes place immediately if a change is made in LSA secrets, for example, when adding a workstation to the domain or changing trusts relationships.
Close of SMB ConnectionsThe following value specifies the maximum amount of time that a connection can be left dormant:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\LanmanWorkstation\ParametersIn a WAN environment, it is preferable to lower this value to 10 seconds on all the servers and the workstations, so that a new ISDN connection is not established just because of a SMB connection close.
Value : KeepConn REG_DWORD 1 to 65535 seconds
Default : 600 (10 minutes)
Changing KeepConn may generate significant SMB overhead. As connections are closed very quickly, each new connection implies the establishment of a new SMB connection.
NetBIOS Name Resolution ModeWhen you use a domain spanning into multiple sites, the NetBIOS name resolution mode should be set to m-node (broadcasts followed by name server) on all servers and workstations.
This setting ensures that a local (for example, on the same subnet) domain controller is always contacted first (for example, before trying to contact the PDC).
On Windows NT systems, the NetBIOS name resolution mode can be set to m-node with the modification of the following key:
Value : NodeType REG_DWORD 4 (4 is for M-NODE)
Trusts RelationshipsUnder certain circumstances, it is possible for 2 PDCs of 2 domains with a trust relationship to generate traffic every 15 minutes. For more information, click the following article number to view the article in the Microsoft Knowledge Base:
152719The following parameter defines the time interval during which Netlogon does miscellaneous work (on the PDC and on the BDCs), for example, finding a domain controller.
(http://support.microsoft.com/kb/152719/ )WAN and Trust: Traffic on the Wire
Value : ScavengeInterval REG_DWORD 60 to 172800 seconds (48 hours)
Default : 900 (15 minutes)
Other Services That Generate TrafficCheck out the configuration of your WINS database renewal interval, and the replicator service as well.
The replicator service may be modified as follows:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Replicator\ParametersFor additional information about how to modify WINS settings, click the article numbers below to view the articles in the Microsoft Knowledge Base:
Value : Interval REG_DWORD 60 (minutes)
Default : 5 (minutes)
Value : Pulse REG_DWORD 6 (6 * 60 minutes = 6 hours)
Default : 3
(http://support.microsoft.com/kb/142305/EN-US/ )Min. and Max. Interval Values for WINS Configuration
(http://support.microsoft.com/kb/135922/EN-US/ )Windows NT Registry Parameters for WINS