Bandwidth usage is much lower than expected after you configure the offline address book Bandwidth Threshold registry entry in Exchange Server 2003 with Service Pack 2 or in Exchange Server 2003 with Service Pack 1

You configure the offline address book Bandwidth Threshold (KBps) registry entry to control the LAN bandwidth usage of users who download the Microsoft Outlook offline address book. When you do this, you do not achieve the results that you want in Microsoft Exchange Server 2003 with Service Pack 2 (SP2) or in Microsoft Exchange Server 2003 with Service Pack 1 (SP1). The bandwidth usage for offline address book downloads is much lower than expected. Users may require extended periods to complete their offline address book downloads.

This problem occurs because Exchange Server does not use the registry entry that is configured.

Hotfix information

A supported hotfix is available from Microsoft. However, this hotfix is intended to correct only the problem that is described in this article. Apply this hotfix only to systems that are experiencing this specific problem. This hotfix might receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next software update that contains this hotfix.

If the hotfix is available for download, there is a "Hotfix download available" section at the top of this Knowledge Base article. If this section does not appear, contact Microsoft Customer Service and Support to obtain the hotfix.

Note If additional issues occur or if any troubleshooting is required, you might have to create a separate service request. The usual support costs will apply to additional support questions and issues that do not qualify for this specific hotfix. For a complete list of Microsoft Customer Service and Support telephone numbers or to create a separate service request, visit the following Microsoft Web site: Note The "Hotfix download available" form displays the languages for which the hotfix is available. If you do not see your language, it is because a hotfix is not available for that language.

Prerequisites

You must install Exchange Server 2003 SP2 before you apply the hotfix.
For more information, click the following article number to view the article in the Microsoft Knowledge Base:

Restart requirement

You do not have to restart the computer after you apply the hotfix. However, the Microsoft Exchange Information Store Service and all dependent services will be restarted.

Hotfix replacement information

This hotfix does not replace any other hotfix.

File information

The global version of this hotfix has the file attributes (or later file attributes) that are listed in the following table. The dates and times for these files are listed in Coordinated Universal Time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time item in Control Panel.

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.

How to configure the offline address book Bandwidth Threshold (KBps) registry entry

Warning Serious problems might occur if you modify the registry incorrectly by using Registry Editor or by using another method. These problems might require that you reinstall your operating system. Microsoft cannot guarantee that these problems can be solved. Modify the registry at your own risk.

1. Click Start, click Run, type regedit in the Open box, and then click OK.
2. Locate and then click the following registry subkey:
   HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\MSExchangeIS\ParametersSystem\
3. On the Edit menu, point to New, and then click DWORD Value.
4. Type OAB Bandwidth Threshold (KBps) for the name of the DWORD, and then press ENTER.
5. Right-click OAB Bandwidth Threshold (KBps), and then click Modify.
6. In the Base area, click Decimal.
7. In the Value data box, type the value that you want to use, and then click OK.
   
   For example, type 5000 to configure the server to use 5000 kilobytes per second (KBps) as the bandwidth threshold for offline address book download throttling. 5000 KBps is approximately 40,960 kilobits per second (Kbps), or 40.96 megabits per second (Mbps).
   
   Use one of the following methods to determine the offline address book Bandwidth Threshold data value to use.

   Set the value preemptively

   You have knowledge of the network topology and of how downloads of the full offline address book from multiple servers can overload the LAN. Use this knowledge to set the thresholds on the individual servers to the largest values that are possible without overloading the LAN.

   Set the value after the fact

   Watch the extended MSExchangeIS Performance Monitor counter (OAB: Full downloads bytes/sec) during a company-wide download that overloads the LAN. Note the bandwidth that is used by offline address book downloads on each server. Then, set the threshold values to a percentage of those values. For example, set the threshold values to 60% of those values.
8. Click OK, and then exit Registry Editor.

For more information about the terminology that Microsoft uses for software that is corrected after it is released, click the following article number to view the article in the Microsoft Knowledge Base: For more information about the naming schema for Exchange software updates, click the following article number to view the article in the Microsoft Knowledge Base: For more information, click the following article number to view the article in the Microsoft Knowledge Base: