Lesson 3: The Schedule FreeBusy Connector | MCSE Training Kit Exam 70-224(c) Microsoft Exchange 2000 Server Implementation and Administration

Free/busy times are the free and busy times of users as noted in their schedules, marked by start and end dates. This information is shared among users so that they can plan meetings and appointments efficiently. A user who wants to book a meeting can view the free and busy times of all attendees and determine a time when they are all available. Using the Schedule+ Free/Busy Connector in conjunction with the MS Mail Connector, you can synchronize free/busy information between MS Mail and Exchange 2000 Server.

This lesson introduces the Schedule+ Free/Busy Connector and explains its architecture and configuration using Exchange System Manager.

At the end of this lesson, you will be able to:

Identify the components of the Schedule+ Free/Busy Connector.
Configure the Schedule+ Free/Busy Connector.

Estimated time to complete this lesson: 45 minutes

Schedule+ Free/Busy Connector Architecture

Free/busy time distribution was introduced with Microsoft Schedule+1.0 in conjunction with MS Mail. Users working with different postoffices can share free/busy information because active processes in the background distribute that information to all postoffices. This feature is also available in Microsoft Schedule+ 7.0, Microsoft Schedule+ 7.5, and Microsoft Outlook and is implemented in Exchange 2000 Server as well.

MS Mail Free/Busy Time Distribution

MS Mail maintains free/busy times on a per-postoffice basis in .pof files, which are in the \Maildata\Cal subdirectory. The file 00000000.POF, for example, contains the free/busy times of users who use the local postoffice. However, the postoffice is a passive file structure. A separate process known as SCHDIST.EXE is required to distribute free/busy information across all postoffices in an MS Mail network.

Three components are very important for free/busy time distribution: SCHDIST.EXE, ADMINSCH.EXE, and a mailbox called Adminsch. As mentioned, SCHDIST.EXE distributes the information across the MS Mail network using e-mail messages, which are sent to the Adminsch mailbox. Once messages are delivered to this mailbox, SCHDIST.EXE can obtain the free/busy information from there to place it in the corresponding .pof files. ADMINSCH.EXE is the Schedule+ Administrator program. You can use it to manage distribution settings, such as the postoffices that receive free/busy information. You should make sure that all target postoffices have an Adminsch account that is included in the MS Mail Dirsync. The MS Mail Dirsync propagates the existence of Adminsch accounts through the MS Mail network.

Schedule+ Free/Busy Information Public Folder

Users with mailboxes on an Exchange 2000 server maintain free/busy information in a hidden system folder in the default public folder hierarchy. You can display this folder in Exchange System Manager. Right-click the default public folder hierarchy (Public Folders), and then select the View System Folders command. A free/busy public folder will exist for each existing administrative group in the Schedule+ Free Busy container. The free/busy public folder is usually on the first server installed in an administrative group. You can replicate it across the organization or move it to a designated free/busy public server. More information about the replication of public folders is provided in Chapter 18, "Public Folder Replication."

Each free/busy public folder contains a single object for each user in its administrative group. These objects store the users' free/busy times. These objects are comparable to regular message items in a visible public folder. If a user stores a free/busy item in this folder, all other users can open it there and read the information. Every user has access to the hidden free/busy public folder when working with Schedule+ 7.0 or later or Outlook.

Schedule+ Free/Busy Connector

The Schedule+ Free/Busy Connector uses the MS Mail distribution protocol to exchange free/busy information between Exchange users and MS Mail users based on e-mail messages. This connector actually accomplishes two tasks. First it creates free/busy messages destined for the MS Mail network. Then it incorporates received information from MS Mail into the free/busy public folder. To access this folder, the connector must communicate with the Information Store service. Once the MS Mail free/busy information is stored on the Exchange 2000 server, users can access it just as any other free/busy information.

The following are the tasks of the Free/Busy Connector:

Obtains free/busy information from the free/busy public folder.
Creates and sends free/busy messages to MS Mail SCHDIST.EXE. Messages are addressed to the Adminsch account of each involved postoffice.
Processes free/busy messages received from MS Mail SCHDIST.EXE. Messages are addressed and delivered to the Adminsch user agent of the Schedule+ Free/Busy Connector.
Places the received free/busy information in the free/busy public folder.

Adminsch User Agent

The Schedule+ Free/Busy Connector uses a user agent called Adminsch to send and receive Schedule+ free/busy information. A user agent is a special Exchange 2000 Server mailbox that is associated with an active service instead of a regular user. It is created during the Free/Busy Connector installation and is in the Connectors container of the Free/Busy Connector's routing group.

SCHDIST.EXE and Adminsch

SCHDIST.EXE sends its local free/busy information to all other Adminsch mailboxes—in other words, to all other SCHDIST.EXE processes in the MS Mail network. SCHDIST.EXE can also include the Exchange 2000 Server in its information distribution since the Schedule+ Free/Busy Connector maintains an Adminsch user agent (see Figure 26.7).

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Figure 26.7 The architecture of the Schedule+ Free/Busy Connector

MS Mail Dirsync

For every Exchange and MS Mail user, a recipient object must exist in Active Directory; otherwise, the Schedule+ Free/Busy Connector will not be able to place free/busy information for the user in the free/busy public folder. Consequently, you need to configure the MS Mail Dirsync and synchronize the address lists before configuring the transfer of free/busy data. Among other things, the MS Mail Dirsync will also replicate the Adminsch accounts, which must exist in each postoffice address list as well as Active Directory to address SCHDIST.EXE messages successfully.

Configuring the Schedule+ Free/Busy Connector

The Schedule+ Free/Busy Connector relies on the MS Mail Connector and the MS Mail Dirsync. The MS Mail Connector must guarantee that free/busy messages arrive at the MS Mail postoffices and that SCHDIST.EXE messages reach the Schedule+ Free/Busy Connector. MS Mail Dirsync, in turn, synchronizes the address information, as mentioned earlier.

Connector Configuration

To configure the Schedule+ Free/Busy Connector, launch Exchange System Manager, and display the properties of the Connector for MS SchedulePlus FreeBusy (<Server Name>) object, which is located in the Connectors container of the connector's routing group. This configuration object provides two tabs, General and Details. As for all configuration objects, the Details tab is less important. It provides only an option to specify an informative Administrative Note. The General tab is more important. Among other things, it allows you to define an Administrator's Mailbox, which is used to store corrupted free/busy messages and messages that could not be processed for other reasons.

NOTE
To have a functioning system, you must configure the MS Mail postoffices using the ADMINSCH.EXE program. The Connector PO must be included in the list of target postoffices.

Sending Free/Busy Information

In the General tab, you will find the Schedule+ Group box, where you need to specify a distribution group that contains the Adminsch accounts of all postoffices you want to include in the free/busy synchronization. Using a distribution list simplifies the task of configuring the connector when several postoffices are included. However, you must create a mail-enabled distribution group for this purpose prior to configuring the connector.

You can select the Send Updates For This Administrative Group Only check box if you want to propagate the free/busy information only of users residing in your administrative group to MS Mail.

Information Updates

By default, the Schedule+ Free/Busy Connector sends changes to free/busy information to the MS Mail network every 15 minutes. This is sufficient for most installations, but you can adjust this in the General tab by using the Update Frequency (Minutes) box. If you discover any inconsistencies between free/busy information in MS Mail and in Exchange, click the Full Export button to send all of the free/busy data to the MS Mail network.