Presence Information - MPOP and Presence By Observation

MPOP and Presence By Observation

Presence becomes interesting for communication systems when it spans a number of different communication channels. The idea that multiple communication devices can combine state, to provide an aggregated view of a user's presence has been termed Multiple Points of Presence (MPOP). MPOP becomes even more powerful when it is automatically inferred from passive observation of a user's actions. This idea is already familiar to instant messaging users who have their status set to "Away" (or equivalent) if their computer keyboard is inactive for some time. Extension to other devices could include whether the user's cell phone is on, whether they are logged into their computer, or perhaps checking their electronic calendar to see if they are in a meeting or on vacation. For example, if a user's calendar was marked as out of office and their cell phone was on, they might be considered in a "Roaming" state.

MPOP status can then be used to automatically direct incoming messages across all contributing devices. For example "Out of office" might translate to a system directing all messages and calls to the user's cell phone. The status "Do not disturb" might automatically save all messages for later and send all phone calls to voicemail.

XMPP, discussed below, allows for MPOP by assigning each client a "resource" (a specific identifier) and a priority number for each resource. A message directed to the user's ID would go to the resource with highest priority, although messaging a specific resource is possible by using the form user@domain/resource.