Calendar querying can be divided into two separate processes: queries that originate from Exchange, and queries that originate from Lotus Notes.
The figure below illustrates the free and busy request process used by Calendar Connector and Lotus Notes.Enlarge figure
When a user on Exchange queries Lotus Notes users for free and busy information, Calendar Connector requests the information using API calls to the Lotus Notes server. The Lotus Notes API is installed with the Lotus Notes client on Exchange. Then the calls are routed to Schedule Manager.
Schedule Manager locates the calendar information for local users in the busytime.nsf database. For users on downstream Lotus Notes servers, Schedule Manager passes the request to the Lotus Notes Calendar Connector task, which then locates the user's calendar information.
Schedule Manager then returns the free and busy information to the Lotus Notes API. On the Exchange server, Calendar Connector receives the Notes free and busy information and translates it into an Exchange format. Calendar Connector then adds the free and busy information to the administrative group's free busy public folder.
When a user on a Lotus Notes system queries for an Exchange users' free and busy information, the request is sent to the Lotus Notes Calendar Connector task. The Lotus Notes Calendar Connector task then sends the request to the Lotus Notes add-in task, called Exchange Calendar Connector (Excalcon.exe). Because all Exchange users are registered in Lotus Notes as belonging to a foreign domain, all requests for Exchange free and busy information are sent from the Lotus Notes Calendar Connector task to Excalcon.exe. Excalcon.exe passes the request from the Lotus Notes system to Exchange through Calendar Connector. Calendar Connector processes the request and queries the Exchange free and busy public folder for the requested information.
Calendar Connector responses are delivered to Excalcon.exe on the Lotus Notes server, which translates the data into Lotus Notes format and delivers the free and busy information to Schedule Manager. Schedule Manager then delivers it to the Lotus Notes client.