The RTC Client API version 1.0 allowed users to publish their location and online status information. RTC Client 1.2 allows users to publish more extensive presence information, including user-defined data if the server supports presence roaming. Starting with RTC Client 1.2, users can log on from multiple devices at the same time and set the online status information for each device separately; users are no longer limited to a single presence device. Watchers will receive the presence information for all the devices that a user is logged onto.
Presence Agent and Presence Agent Server
With RTC Client API version 1.0, the client application acted as the Presence Agent (PA) for the user. The contact list was stored on the local machine and the presence information for each active contact was also stored on the local machine. This limited the user to a single presence device that stored all the contact information. Starting with RTC Client 1.2, the server acts as the Presence Agent Server (PAS) for the client if the roaming features for presence are enabled. When the server acts as the PAS, the server handles PA functionality for the client. The client supplies presence information to the server, and the server distributes this information to the watchers.
Setting Presence Information
The following sections contain information on setting and retrieving presence information.