NetLogon Maximum Value of Pulse Should Exceed 3600

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Article ID: 150350 - View products that this article applies to.
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Your ISDN TCP/IP router telecommunication connection costs appear to be very high.
  • Your network spans two or more sites.
  • You use ISDN TCP/IP routers.
  • You use an ISDN service that charges you based on connection time.


  1. Install Windows NT 3.51 Service Pack 5. WARNING: Using Registry Editor incorrectly can cause serious, system-wide problems that may require you to reinstall Windows NT to correct them. Microsoft cannot guarantee that any problems resulting from the use of Registry Editor can be solved. Use this tool at your own risk.

  2. Go to the following key in the Registry:

You can now set the pulse to a maximum of 172800 (2A300h).


Microsoft has confirmed this to be a problem in Windows NT version 3.51. This problem was corrected in the latest Windows NT 3.51 U.S. Service Pack. For information on obtaining the Service Pack, query on the following word in the Microsoft Knowledge Base (without the spaces):


The following example outlines a common scenario involving ISDN routers.

One primary domain controller (PDC), with a significant number of backup domain controllers (BDCs), connects to one PDC via ISDN. Each time a network frame is exchanged between a BDC and the PDC, it costs one ISDN connection.

PDC parameters:

- Pulse = 3600 seconds = 1 hour
- PulseConcurrency = 1 - 10

In this case, the PDC may handle many user account transactions so that SAM changes are common and occur often. Each time the PDC detects a SAM change, it contacts all the BDCs. Having purchased ISDN routers, the you may not necessarily desire to have the BDC's SAMs updated every hour. Because of the cost of activation, you may want to update the BDCs as little as once every 48 hours.

Currently, if the Pulse parameter is set to its maximum, the cost for transaction updates is the number of BDC connections every hour. If there are 50 BDCs, there are 50 connections per hour. For 120 BDCs, the cost is 120 connections per hour.

Looking at this on a monthly basis, the cost of connections becomes even more apparent: 120 connections x 24 hours a day x 30 days a month = 86,400 connections.

NOTE: For additional information on reducing domain browsing and WINS replication traffic over slow links, please see the following article in the Microsoft Knowledge Base:

134985Browsing & Other Traffic Incur High Costs over ISDN Routers


Article ID: 150350 - Last Review: September 30, 2013 - Revision: 3.1
  • Microsoft Windows NT Workstation 3.51
  • Microsoft Windows NT Server 3.51
kbnosurvey kbarchive kbnetwork KB150350

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