Presence
Messaging technology that lets users or devices quickly find each other, no matter their physical location. RFC 2779, which defines some presence requirements, says:
"Presence is a means for finding, retrieving, and subscribing to changes in the presence information (e.g. 'online' or 'offline') of other users."
An example of a presence system is instant messaging, such as
AOL Instant Messenger or
Lotus Sametime. In a typical presence network, a central server or servers keeps track of users as they log into and out of the network.
The promise of presence technology is that users can reach others instantly regardless of location of either party, over a variety of media, including chat, video and wireless or traditional voice. Also possible will be technologies such as spontaneous audio- and videoconferences.
Key to many presence initiatives are SIP, a signaling standard for setting up and managing communications sessions between different media and the related SIP for Instant Messaging and Presence Leveraging Extensions, now progressing as a uniform way to add presence to those capabilities.
Additional resources
Latest presences news and analysis from Network World.
Boosting your IM IQ will pay off
Network World, 03/11/02.
Instant Messaging / Presence Protocol Requirements
RFC 2779.
Common Presence and Instant Messaging (CPIM)
IETF draft on proposed standardized services for IM and presence systems.
Jabber
Open protocols for IM and presence software.
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